Saudi-led warplanes bombed Yemen's main international airport and struck a renegade troop base in the capital, as Arab leaders vowed Sunday to pummel Iranian-backed rebels until they surrender.

The raids on the country's main air gateway came just hours after UN workers were evacuated following deadly fighting that has sent tensions between Tehran and other Middle East powers soaring.

India and Pakistan also moved to airlift their citizens from the chaos-wracked country.

Yemen's President Abedrabbo Mansour Hadi has urged his Arab allies to keep up the bombing until the Huthi Shiite rebels are defeated, branding them Iran's "puppet".

His Foreign Minister Riyadh Yassin said there could be "no negotiations and dialogue" with the rebels "until the legitimate government has control over all Yemeni lands".

Arab League chief Nabil al-Arabi said at a regional summit in Egypt on Sunday the offensive would go on until the rebels "surrender" their weapons and withdraw from areas they seized.

The Huthis and allied renegade military units have overrun much of the country and prompted Hadi to flee what had been his last remaining refuge in the main southern city Aden for Saudi Arabia.

Dozens of people have been killed in clashes in Aden in recent days, dimming prospects of Hadi returning any time soon.

At least 38 people were killed Sunday in fighting near the oil region of Usaylan in southern Shabwa province after tribesmen attacked rebel positions, security and tribal sources said.

In the capital, witnesses reported hearing three loud explosions and seeing a large fire when Sanaa International Airport was bombed during a fourth night of Saudi-led air raids.

- Foreigners flee -

"This was the first time they hit the runway" since the campaign began, an aviation source said. "The airport is completely out of service."

A civil aviation official at the airport later told AFP that work to repair the runway had begun.

More than 200 staff from the UN, foreign embassies and other organisations had been flown out from the airport on Saturday.

A jumbo jet sent by Pakistan flew out of Hodeida in western Yemen Sunday with nearly 500 of its citizens on board, including the ambassador, officials said.

India said it had received permission from the Arab coalition to airlift out its stranded citizens and would also send a ship.

Overnight air strikes hit the headquarters of the rebel republican guard at Al-Subaha base in Sanaa, killing 15 soldiers, a military official said.

The Huthis are backed by army units loyal to former president Ali Abdullah Saleh, who stepped down in 2012 after a year-long popular uprising and is accused of supporting the rebels.

The latest Saudi-led strikes also hit an airbase in rebel-held Hodeida, witnesses said.

Other raids targeted a base of the First Artillery Brigade in Saada, the northern stronghold of the Huthis.

Spokesman Ahmed Assiri told reporters in Riyadh that the "coalition operations will increase pressure on Huthi militia" who will "no longer have a safe haven within Yemen".

At the regional summit in Sharm el-Sheikh, Egyptian President Abdel Fattah al-Sisi said Arab leaders had "agreed on the principle" of creating a joint military force.

The proposal has taken on added urgency since the Huthis seized swathes of Yemen, although Saudi Arabia has said there are no immediate plans to send in ground troops.

The Sunni Arab coalition is said to have been spurred into action by the prospect of a Shiite Iran-backed regime seizing power in impoverished Yemen, wedged on the southern tip of the Arabian Peninsula.

- Russian concerns -

Russia has voiced concern that the clashes could undermine nuclear negotiations between world powers and Iran in the Swiss city of Lausanne, although diplomats said a tentative deal was emerging.

In talks with Yassin in Egypt, Russian deputy foreign minister Mikhail Bogdanov called on "all sides of the conflict to cease military action in the name of preserving the unity, sovereignty and territorial integrity of Yemen", his ministry said.

Israeli Prime Minister Benjamin Netanyahu, a vociferous critic of Tehran, denounced the "Iran-Lausanne-Yemen axis which is dangerous for all of humanity and which must be stopped".

According to Saudi Arabia, more than 10 countries have joined the coalition defending Hadi. Washington and Britain have pledged logistical support.

Late Saturday, anti-Huthi local fighters were reported to have taken full control of Aden airport with the loss of five men, and nine rebels killed.

The rebels also set up a base in Dar Saad on the city's northern fringe after clashes in which six people, including four Huthis, were killed, a military source said.

Nearly 100 people are reported to have died in violence in Aden in recent days.