A senior US official said Tuesday that Russia's plan to acquire hundreds of combat drones from Iran shows its urgent need to reinforce due to heavy losses four months after invading Ukraine.

John Kirby, a spokesman for the national security council, said the deal, revealed by the White House on Monday, also shows Iran's willingness to support Moscow's war on Ukraine.

But he said supply the drones would not necessarily affect US ongoing attempts to negotiate a return to the 2015 six-party deal to prevent Tehran from developing nuclear weapons.

A man who US officials called the leader of the Islamic State militant group in Syria was killed Tuesday in a drone strike while riding a motorcycle in the northern part of the country, the Pentagon and local organizations said.

Maher al-Agal was killed near Jindires in northern Syria, and one of his top aides was seriously injured in the attack, Pentagon Central Command spokesman Lieutenant Colonel Dave Eastburn told AFP.

The volunteer Syrian Civil Defense Force, known as the "White Helmets," said the attack targeted the two while they were on a motorcycle outside Aleppo.

The UN Security Council adopted a resolution Tuesday extending a system for cross-border aid to Syria by six months, the duration demanded by Russia while other members had sought a full year.

The measure received support from 12 of the Security Council's 15 members, including Russia, China, and the grouping's 10 non-permanent members.

Western nations had called for a year-long extension, arguing that six months was insufficient to properly plan the delivery of aid to war-ravaged Syria.

Ahead of Joe Biden's first visit to Jerusalem as US president, Washington's ambassador said his team will "pound tables" to press Israeli officials into making concessions to the Palestinians.

But ambassador Thomas Nides was talking about ensuring Palestinians have access to economic benefits such as 4G internet, not throwing American diplomatic muscle into reviving a peace process moribund since 2014.

Iraqi Kurd Haresh Talib says he struggles to get paid and his children's schooling is disrupted in his conflict-riddled country, so he wants to try to flee with his family to Europe -- again.

"There is no future here," says the 36-year-old from the autonomous Kurdistan region in Iraq's north.

Talib, his hair gelled back and beard neatly trimmed, lives on the first floor of a pastel yellow house with his wife, two sons and a pet bird in a well-kept neighbourhood of Sulaimaniyah, Kurdistan's second-largest city.

Iran is planning to supply hundreds of drones with combat weapon capabilities to Russia for use in Ukraine, a top US official said Monday.

Jake Sullivan, the White House national security advisor, said the information received by the United States supported views that the Russian military is facing challenges sustaining its weaponry after significant losses in Ukraine.

"The Iranian government is preparing to provide Russia with up to several hundred UAVs (unmanned aerial vehicles), including weapons-capable UAVs, on an expedited timeline," Sullivan told reporters.

The UN Security Council has agreed to extend a vital system for cross-border aid to war-ravaged Syria by six months, the length of time wanted by Russia, diplomats told AFP Monday.

Western nations had demanded a year-long extension, but a vote by the 15 members on half that is expected either later in the day or Tuesday.

"Russia forced the hand of everyone. Either close the mechanism or only six months. We cannot let people die," one ambassador told AFP on condition of anonymity.

Iranian director Jafar Panahi, renowned for his gritty social commentary which has drawn the ire of his country's rulers, was arrested on Monday -- the third filmmaker to be held in less than a week.

Panahi, 62, was outlawed from making movies and leaving the country after supporting mass protests in 2009 and making a series of films that critiqued the state of modern Iran.

His fellow filmmakers Mohamad Rasoulof and Mostafa Aleahmad were arrested separately over events relating to a deadly building collapse in the city of Abadan which sparked angry protests.

Award-winning dissident Iranian film-maker Jafar Panahi was arrested Monday, the third director to be detained in less than a week, the Mehr news agency said.

Panahi, 62, has won a slew of awards at international festivals for films that have critiqued modern Iran, including the top prize in Berlin for "Taxi" in 2015, and best screenplay at Cannes for his film "Three Faces" in 2018.

"Jafar Panahi has been arrested today when he went to the prosecutor's office to follow up on the situation of another film-maker, Mohammad Rasoulof," Mehr reported.

A Saudi dissident living in Lebanon was killed in the Beirut suburbs and two of his brothers arrested in connection with the incident, Lebanese police and a security source said Monday.

The victim was stabbed to death on Saturday in his home in a southern Beirut area known to be under the security control of Hezbollah, a Shiite organisation backed by Saudi arch foe Iran.

His brothers confessed to killing him "for family reasons", a statement by Lebanon's Internal Security Forces said.