The United Nations expressed deep alarm on Monday at reports that US strikes on Yemen killed scores of people at a migrant detention centre in a stronghold of the Huthi rebels.

The US military has hammered the Iran-backed Huthis with near-daily strikes since March 15 in an operation dubbed "Rough Rider", seeking to end their attacks on vessels in the Red Sea and Gulf of Aden.

Huthi-controlled media said the latest strikes on the movement's stronghold of Saada killed at least 68 people, all Africans being held at a "centre for illegal migrants".

The UN's top court will on Monday open a week of hearings on Israel's humanitarian obligations towards Palestinians, more than 50 days into its total blockade on aid entering war-ravaged Gaza.

United Nations representatives will start the five days of sittings at the International Court of Justice in The Hague at 10:00 am (0800 GMT), followed by a Palestinian submission.

Another 38 countries will then address the 15-judge panel, including the United States, China, France, Russia and Saudi Arabia.

At the break of dawn, 10-year-old Youssef al-Najjar races barefoot, clutching a battered pot, to a community kitchen in Gaza City, only to find hundreds of others already queueing.

"People push and shove out of fear of missing their turn. There are little children who fall," said Youssef, his voice barely rising above a whisper.

Thousands of Gazans, including many children, rush to community kitchens every day in the hope of securing food for their families.

Catholic cardinals agreed on Monday to begin a conclave on May 7 to elect a new pope, and highlighted clerical sexual abuse as one of the key challenges facing Pope Francis's successor.

Cardinals under the age of 80 will meet in the Sistine Chapel to choose a new leader for the world's 1.4 billion Catholics, in a mystery-shrouded ritual dating back to the Middle Ages.

The date was decided at a meeting of cardinals of all ages early on Monday, two days after the funeral of Francis, who died on April 21 aged 88.

The United States has hit more than 800 targets in Yemen since mid-March, killing hundreds of Huthi rebel fighters, including members of the group's leadership, the US military said Sunday.

Washington's forces have hammered the Huthis with near-daily air strikes since March 15 in an operation dubbed "Rough Rider," seeking to end the threat they pose to vessels in the Red Sea and Gulf of Aden and reestablish US regional "deterrence."

Israel struck south Beirut on Sunday for the third time since a fragile November 27 ceasefire, prompting Lebanese President Joseph Aoun to call on its guarantors France and the United States to force a halt.

But Israeli Prime Minister Benjamin Netanyahu's office said the strike targeted a building used by Hezbollah to store "precision-guided missiles" and vowed to stop the Iran-backed militant group using Beirut's southern suburbs as a "safe haven".

An AFP correspondent saw a plume of smoke rising over the building in the Hadath neighbourhood after the strike.

The health ministry in Hamas-run Gaza announced Sunday that the death toll from the war had risen to more than 52,000 people, after hundreds previously listed as missing were confirmed dead.

"An additional 697 martyrs have been added to the cumulative statistics after their data was completed and verified by the committee monitoring missing persons," the health ministry said in a statement, giving the overall toll of 52,243.

Iran's supreme leader Ayatollah Ali Khamenei ordered a thorough investigation Sunday into the causes of a major blast at a key southern port that killed at least 40 people and injured more than 1,000.

His instructions came after President Masoud Pezeshkian visited the blast scene in Shahid Rajaee Port near the strategic Strait of Hormuz where a fire still blazed on Sunday more than 24 hours after the explosion.

Palestinian president Mahmud Abbas appointed a close aide as the first ever vice president of the Palestine Liberation Organization (PLO) on Saturday, positioning him as a potential successor to the veteran leader.

Hussein al-Sheikh was appointed by Abbas, 89, after the vice presidency position was created during a convention held in Ramallah this week.

The new post follows years of international pressure to reform the PLO and comes as Arab and Western powers envision an expanded role for Abbas's Palestinian Authority (PA) in the post-war governance of the Gaza Strip.

Syria's Kurdish parties on Saturday adopted a joint political vision calling for a "decentralised democratic" state in Syria with guarantees for Kurdish rights.

Their statement came at the end of a conference held in Qamishli, northeastern Syria, where a top Kurdish official disputed suggestions that the meeting sought division following the fall of longtime ruler Bashar al-Assad.

Syria's new Islamist-led rulers seek to establish government control over the entire country since they ousted Assad in December after more than 13 years of civil war.