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.

Israel ordered an immediate halt to Gaza's electricity supply Sunday in an effort to pressure Hamas into releasing hostages, even as it prepared for fresh talks on the future of its truce with the Palestinian militants.

Israel's decision comes a week after it blocked all aid supplies to the war-battered territory, a move reminiscent of the initial days of the war when Israel announced a "siege" on Gaza.

Hamas described the electricity cut as "blackmail," a term it had also used after Israel blocked the aid.

The new CEO of LIV told AFP the world of golf will eventually "open up again" and the Saudi-bankrolled league has an important role in growing the game around the world.

American sports executive Scott O'Neil, who has in the past run NBA and NHL teams, took the reins from Greg Norman in January.

The period since has seen a flurry of meetings between the PGA Tour, LIV Golf and their Saudi backers, the Public Investment Fund (PIF), but still no deal reached to reunite the sport.

Protesters took to the streets across the world Saturday to mark International Women's Day, demanding equal pay, political representation and an end to gender-based violence while voicing fears of rising repression.

In eastern Ukraine, scores of demonstrators held a minute's silence to honour women killed defending the country from Russia's invasion. Many carried banners bearing the faces of the deceased.