President Joe Biden took office vowing to negotiate an end to a bloody war in Yemen and to remove US troops from harm's way.

He enters his reelection year by launching strikes on the country instead, but his administration hopes calm can return.

Experts say the Biden administration and Yemen's Huthi insurgents, as well as the group's backers in Iran, have tacitly entered a delicate and dangerous understanding -- they both feel the need to use force, while presuming the other side does not want to escalate.

Two-goal Akram Afif said Qatar had "forgotten about the World Cup" after the defending champions got their Asian Cup campaign off to a winning start in the tournament's opening game on Friday.

The hosts beat Lebanon 3-0 at the 88,000-capacity Lusail Stadium, where a Lionel Messi-inspired Argentina beat France on penalties in the World Cup final 13 months ago.

Qatar suffered a disastrous 2022 World Cup on the pitch, making a first-round exit after losing all three games, the worst performance by a host in the history of the competition.

Friday's opening ceremony of the Asian Cup drew attention to the war in Gaza, with Palestine's captain taking the stage for the players' oath and Palestinian music at the beginning and end.

Ahead of the opening game between hosts Qatar and Lebanon at the 88,000-capacity Lusail Stadium, home captain Hassan Al-Haydos introduced his Palestinian counterpart Musab Al-Battat to deliver the players' oath, traditionally taken by the host nation's captain, on his behalf.

Battat wore the traditional Palestinian keffiyeh headscarf along with his team tracksuit.

United Nations Secretary-General Antonio Guterres called on all sides "not to escalate" the volatile situation in the Red Sea, his spokesman said on Friday after Washington and London launched strikes on Yemen's Huthi rebels.

The barrage of strikes early on Friday against the Huthis, who say they are acting in solidarity with Gaza, follow weeks of disruptive rebel attacks on Red Sea shipping and have stoked fears of the Israel-Hamas war spreading regionwide.

Cyprus is "not involved" in military action against Yemen's Huthi rebels, the foreign ministry said Friday, after aircraft stationed at a British base on the island joined US-led strikes on the rebels.

Britain has retained sovereign control over two base areas in its former colony under the terms of the treaties that granted the island independence in 1960.

Hundreds of thousands of people, some carrying Kalashnikov rifles, massed for a major demonstration in Yemen's rebel-held capital Sanaa on Friday after US and UK attacks.

Crowds under a sea of Yemen and Palestinian flags chanted "Death to America, death to Israel" as they massed in the giant Sanaa square in the historic city's centre.

The Iran-backed Huthi rebels, who seized Sanaa in 2014 and have been at war with a Saudi-led coalition, came under heavy bombardment overnight with a series of military targets hit.

The deadly Hamas attack on Israel may have taken the limelight from the Islamic State group, but the jihadists are seeking to capitalise on anger over the bombardment of Gaza to rally followers, analysts say.

Israel has vowed to defeat Hamas after an attack on its soil by the Palestinian militant group on October 7 that killed around 1,140 people, mostly civilians, according to an AFP tally based on official figures.

Militants also took around 250 hostages, 132 of whom Israel says remain in Gaza, including at least 25 believed to have been killed.

US and British strikes on rebel-held Yemen on Friday marked a sharp escalation after weeks of attacks on Red Sea shipping by the Iran-backed Huthi insurgents.

AFP examines the impact and possible repercussions of the aerial assault on the Huthis, who say they are targeting Israel-linked vessels in retaliation for the war in Gaza.

- What happened in the strikes? -

More than 100 precision-guided munitions struck 60 targets at 16 locations in an attack involving fighter jets and Tomahawk missiles, US Central Command said in a statement.

Effi Hajaj has reopened his seafront stall in south Israel's Ashkelon, offering coffee and snacks to beach-goers who are back in what he called a "victory" after almost 100 days of war.

Were it not for the sound of explosions from the besieged Gaza Strip, about 10 kilometres (six miles) down the coast, it may have appeared as a perfectly quiet day on the sandy beach.

"Victory means a return to routine, and a certain routine has returned," said 55-year-old Hajaj, whose business like many others had been shut after Hamas's October 7 attack.

Overnight strikes in Yemen have set off alarm bells in Saudi Arabia, which craves de-escalation in its war-torn neighbour so it can focus on domestic reforms, analysts said.

Explosions lit up the night sky early on Friday as the United States and Britain pounded scores of targets with more than 100 precision-guided munitions, US Central Command said.

The strikes came in response to weeks of disruptive attacks on Red Sea shipping by the Iran-backed Huthis, who control northern Yemen and say they are firing on Israel-linked ships in solidarity with Palestinians in Gaza.