Before the start of business, Just Security provides a curated summary of up-to-the-minute developments at home and abroad. Here’s today’s news.

SAUDI ARABIA

President Obama in Saudi Arabia. Obama met today with senior officials from six Arab states in Riyadh, to discuss security issues affecting the Persian Gulf, including the fight against ISIS. The meetings are intended to build on a similar event convened last year at Camp David. [AP]  The president met yesterday with King Salman of Saudi Arabia, the leaders spending more than two hours in a private meeting which officials said was cordial but reflected differences between the two on major issues like Iran, human rights and the international terror threat, report Michael D. Shear and Ben Hubbard. [New York Times]  Joining Obama on the visit, Defense Secretary Ash Carter met with regional security officials yesterday, saying he encouraged them to do more militarily, politically and economically. [Wall Street Journal’s Colleen McCain Nelson and Margherita Stancati]

Analysis and comment. President Obama received a “chilly reception” upon arrival in Riyadh, comments Ian Black, noting that the president’s arrival at the airport was not broadcast live on Saudi TV, as is routine with visits from heads of state. [The Guardian]  Ray Takeyh argues that President Obama’s visit to Saudi Arabia is “futile,” arguing that the two allies now see little in the same way. [Politico Magazine]  And Nicholas Kristof argues that “Saudi Arabia legitimizes Islamic extremism and intolerance around the world,” arguing that if the international community wants to stop attacks like Brussels and San Bernardino, it needs to “turn off the spigots of incitement” from Riyadh. [New York Times]

CYBERSECURITY, PRIVACY and TECHNOLOGY

A coalition of tech companies is opposing an encryption bill that would require its members to disclose customer data to the government. Apple, Facebook, Google, Microsoft, Twitter and other firms have sent a letter to the bill’s backers calling it “unworkable.” [The Hill’s Cory Bennett]

“What rules should apply to government hackers?” As the debate over regulating encryption begins to resolve itself into a discussion on “lawful hacking,” Jenna McLaughlin considers what the rules of this new “game” might be. [The Intercept]

The US is wary of reopening negotiations on the EU-US Privacy Shield data transfer agreement after concerns were raised by the EU last week, the US Undersecretary of Commerce for International Trade has said. The agreement was made in February following two years of negotiations. [Reuters’ Julia Fioretti]

UK intelligence services have been covertly collecting bulk personal data on people who are “unlikely to be of intelligence or security interest” since the late 1990s, internal MI5, MI6 and GCHQ documents obtained by Privacy International have revealed. The documents indicate that successive ministers have been aware of what may amount to “mass surveillance.” [The Guardian’s Owen Bowcott and Richard Norton-Taylor; Financial Times’ Kate Allen]

IRAQ and SYRIA

Moscow has positioned artillery units in parts of northern Syria where the government has massed forces, sparking US concern that the allies may be planning a full-scale return to fighting as the current cessation of hostilities falters. [Wall Street Journal’s Adam Entous and Gordon Lubold]

Syria’s foreign minister accused Turkey and other states of supplying weapons to terrorists in Syria, state media reported. [Reuters’ John Davison and Omar Fahmy]

A major evacuation operation is underway in Syria, relief agencies evacuating people from four besieged towns, the largest such operation in five years of conflict. [BBC]

The UK Parliament has declared atrocities committed by ISIS as genocide, specifically their treatment of Yazidis and Christians. The unanimous vote in the House of Commons was in defiance of the government position, the Foreign Office saying it would be unwise to prejudge the issue or act as jury on a case that may reach the ICC. Patrick Wintour reports. [The Guardian]

The conditions required to defeat ISIS in Syria and Iraq are “in the process of coming together,” said French Defense Minister Jean-Yves Le Drian today, report Emmanuel Jarry and James Regan. [Reuters]

US-led airstrikes continue. The US and coalition military forces carried out three strikes against Islamic State targets in Syria on April 19. Separately, partner forces conducted a further 21 strikes against targets in Iraq. [Central Command]

EUROPEAN TERROR THREAT

The German Federal Constitutional Court ruled that important antiterrorism laws are partly unconstitutional yesterday, demanding tighter control over surveillance. The law will stay in place subject to limitations. [DW; New York Times’ Alison Smale]

President Obama will discuss counterterrorism strategy with European leaders on Monday, the White House has announced. The meeting on April 25 will be attended by French President François Hollande, German Chancellor Angela Merkel, British Prime Minister David Cameron and Italian Prime Minister Matteo Renzi. [The Hill’s Jordan Fabian]

There are around 200 Belgians fighting for Islamic State in Syria who are “possibly coming back” to Europe in order to carry out terrorist attacks, Belgian’s interior minister said today. [Wall Street Journal’s Valentina Pop]

AFGHANISTAN

Tuesday’s large-scale bomb attack in Kabul, Afghanistan, is a sign that the Taliban “could be acquiring more powerful explosives,” Afghan security officials warned yesterday. The attack, in which 64 people were killed, is one of the deadliest since the Taliban insurgency began in 2001. [Washington Post’s Tim Craig and Sayed Salahuddin]

The attack raises the question of how the Taliban was able to gain entry to the National Directorate of Security, the Afghan intelligence agency that was targeted, and has increased the pressure on Afghanistan’s coalition government to get itself in order, write Mujib Mashal and Jawad Sukhanyar. [New York Times’]

US drone strikes now outnumber warplane attacks in Afghanistan, US Air Force data for 2015 show, an illustration of the reliance the US military places on unmanned aircraft nowadays. [Reuters]

The Taliban “do look a lot like they are winning” in Afghanistan, writes Nick Paton Walsh, who suggests that President Ashraf Ghani’s government’s failures are due to the fact that it has mistaken perception for reality, focusing on “message” rather than “results.” [CNN]

China is hoping to establish stronger military ties with Afghanistan, a senior Chinese officer has informed a visiting Afghan convoy. China, Pakistan and the US are currently attempting to broker peace talks to end the Taliban insurgency, but the militants have so far refused to take part. [Reuters’ Ben Blanchard]

ISRAEL and PALESTINE

Hamas has claimed responsibility for the bomb attack on a bus in Jerusalem earlier this week, announcing via its media that 19-year-old Abdel Hamid Abu Srour carried out the attack, though none of its top officials have issued a statement. [Washington Post’s William Booth; Ynet News]

A network of Jewish extremists has been uncovered in the West Bank, Israel’s police and domestic security agency announced yesterday. They said that the network is responsible for several attacks on Palestinians in recent times. [New York Times’ Isabel Kershner]

Terror incidents on the West Bank have “declined significantly” since last December, reports Neri Zilber, who discusses the factors which may have contributed to this, including “security cooperation” between Israel and Palestine. [The Daily Beast]

Hezbollah has over 100,000 rockets and missiles and presents an “unprecedented” threat to Israel, Israel’s deputy chief of staff Major General Yair Golan told reporters yesterday, with the warning that Israel would utilize its full military capabilities if another Israel-Hezbollah war were to take place, resulting in “devastating” damage in Lebanon. [Al Jazeera]

CHINA

China’s actions in the South China Sea raise “serious questions” about its “intentions,” Deputy Secretary of State Anthony Blinken told students at Vietnam’s National University in Hanoi today. He said that the US and Vietnam “share the interest in maintaining peace and stability in the region.” [AP]

China’s President Xi Jinping has given himself the new title of commander in chief of the Chinese military’s Joint Operations Command Center, a position that will provide him with a more direct role in military affairs allowing him to “command personally.” [AP]

NORTH KOREA

North Korea may have recommenced tunneling at its main nuclear test site, satellite images interpreted by the John Hopkins University School of Advanced International Studies indicate. [Reuters’ David Brunnstrom and Jack Kim]

US-China cooperation against North Korea is “stronger.” A US envoy for North Korea told reporters in Beijing today that the two nations took an equal part in drafting the UN Security Council’s resolution imposing sanctions on North Korea back in March. [AP]

OTHER DEVELOPMENTS

The Pentagon has submitted a request to Congress to allow parts of the Guantánamo Bay war court trials to be conducted via video link, in an effort to expedite proceedings. [Miami Herald’s Carol Rosenberg]

What’s in the missing 28 Pages? Officials have informed reporters that the still-classified chapter of the 2002 joint inquiry report into 9/11 will serve only to “flesh out the details” of what is already known to authorities and members of the public, and that there are “thousands” of other documents, still classified, that would reveal “far  more.” [NBC News’ Josh Meyer]

Yemen peace talks will begin today, according to the UN. A rebel delegation departed from Sana’a yesterday to join the talks in Kuwait. [BBC]  A political deal is “remote” while Iran continues to supply Houthi rebels with training and weaponry, says Luke Coffey. [Al Jazeera]

Islamic State and Boko Haram are beginning to collaborate more closely, according to US military officials. Boko Haram pledged allegiance to Islamic State last year. [New York Times’ Helene Cooper]

Boko Haram is “luring” young people to join it with business loans, the Nigerian military has reported. Once the loans are given, the borrower is faced with the “option” of either joining the group or being killed if they fail to repay the loan when it becomes due. [CNN’s Radina Gigova]

The meeting between Russia and NATO on Wednesday was “constructive and substantive,” according to officials, though no agreements were reached. “NATO allies and Russia hold very different views,” NATO Secretary-General Jens Stoltenberg said following the meeting. [Wall Street Journal’s Julian E Barnes and Paul Sonne]

The US Supreme Court ruled that almost $2 billion-worth of frozen Iranian funds will be paid out to Americans found to have been victims of Iranian terrorist attacks yesterday. [NPR’s Eyder Peralta]

Police officers guarding a polio vaccination campaign in Karachi, Pakistan, were gunned down yesterday. No one has claimed responsibility for the attack so far, though the Taliban have repeatedly targeted health workers in the past, report Zia ur-Rehman and Salman Masood. [New York Times]