Immigration officers have arrested a leader of the protests at Columbia University against Israel's war in Gaza, authorities said Sunday, after US President Donald Trump vowed to deport foreign pro-Palestinian student demonstrators.

Mahmoud Khalil, one of the most prominent faces of the university's protest movement that erupted in response to Israel's conduct of the war, was arrested on Sunday, the Department of Homeland Security (DHS) said on X.

Ukrainian President Volodymyr Zelensky is due to arrive in Saudi Arabia on Monday, a day ahead of crucial talks between Ukrainian and US officials on ending the war with Russia.

Highly anticipated negotiations on Tuesday on resolving the three-year conflict will see US and Ukrainian officials meet for the first time since Zelensky's disastrous White House visit last month.

Zelensky said he would on Monday meet Saudi Crown Prince Mohammed bin Salman, the country's de facto leader, after which his team "will stay for a meeting on Tuesday with the American team".

Israel's negotiating team left for Qatar Monday for talks aimed at extending the fragile Gaza ceasefire after the authorities cut the Palestinian territory's electricity supply to ramp up pressure on Hamas.

Ahead of the negotiations, Israel disconnected the only power line to a water desalination plant in Gaza, a move Hamas denounced as "cheap and unacceptable blackmail".

The first phase of the truce deal expired on March 1 with no agreement on subsequent stages that should secure a lasting end to the war that erupted with Hamas's October 7, 2023 attack on Israel.

Syrian security forces on Sunday fired in the air to disperse rival protests after pro-government demonstrators clashed with a gathering mourning dead civilians, following the reported mass killings of Alawites.

The incident came after deadly violence in Syria's Alawite heartland that saw hundreds killed, according to a war monitor, in attacks targeting the religious minority or in clashes between security forces and armed groups loyal to toppled president Bashar al-Assad.

US Secretary of State Marco Rubio set off on Sunday to fly to Saudi Arabia for talks with Ukraine, as President Donald Trump decides whether to relent on a freeze in military and intelligence support.

Rubio will then travel on to Group of Seven (G7) talks in Canada, making him the first major US official to visit since Trump returned to office, launched a trade war the neighboring country and mocked its sovereignty.

The US envoy who held unprecedented direct talks with Hamas said Sunday the meeting had been "very helpful" and he was confident a hostage release deal could be reached "within weeks."

Speaking to CNN, Adam Boehler acknowledged that as a Jewish American it had been "odd" sitting face-to-face with leaders of a group that the United States has listed as a "terrorist" organization since 1997, but he did not rule out further meetings with the Palestinian militants.

A prominent French journalist on Sunday announced he was stepping down from his role as an expert analyst for broadcaster RTL after provoking an uproar by comparing French actions during colonial rule in Algeria to a World War II massacre committed by Nazi forces in France.

Jean-Michel Aphatie, a veteran reporter and broadcaster, insisted that while he would not be returning to RTL he wholly stood by his comments made on the radio station in late February equating atrocities committed by France in Algeria with those of Nazi Germany in occupied France.

For two days, Rihab Kamel and her family hid terrified in their bathroom in the city of Baniyas as armed men stormed the neighbourhood, pursuing members of Syria's Alawite minority.

The coastal city is part of Syria's Alawite heartland that has been gripped by the fiercest violence since former president Bashar al-Assad was toppled in December.

"We turned off the lights and hid. When we were able to flee our neighbourhood of Al-Qusour, we found the roads full of corpses," Kamel, a 35-year-old mother, told AFP.

Iran said Monday it would not negotiate under "intimidation", after US President Donald Trump sought to ratchet up pressure on Tehran by ending a sanctions waiver that had allowed Iraq to buy electricity from its Shiite neighbour.

Iran's mission to the United Nations had indicated Sunday that Tehran might be open to talks aimed at addressing US concerns about the potential militarisation of its nuclear programme -- though not to ending the program completely.

Syria's new leader has vowed accountability and an investigation after reports of mass killings of Alawite civilians triggered an international backlash against the worst violence since Bashar al-Assad's overthrow.

In its latest toll Monday, the Syrian Observatory for Human Rights war monitor said 973 civilians had perished since March 6 in "killings, field executions and ethnic cleansing operations" by security personnel or pro-government fighters in the coastal heartland of the Alawite minority community to which the toppled president belongs.