Egypt's president, Abdel Fatah al-Sisi, has backed calls to create a unified Arab force to confront regional security threats, and said intervention in Yemen was the "inevitable" result of meddling by a foreign power.

Speaking at an Arab League summit, he said that the military campaign against Shia Houthi militias in Yemen, which has been led by Saudi Arabia, aimed to "preserve Yemen's unity and the peace of its territories".

Sisi was backed by Saudi Arabia's King Salman, who vowed that the military intervention in Yemen would not stop until the country was stable and safe.

The Egyptian president said the Arab world was facing unprecedented threats and, without mentioning it by name, accused Shia, non-Arab Iran of meddling in Arab affairs. He also blamed Shia rebels for creating chaos in the country, calling them "stooges of Iran".

The campaign of air strikes by a Saudi-led coalition of 10 nations was in response to a power grab in the impoverished nation by Iranian-backed Shia rebels known as the Houthis. Iran and the Houthis deny that Tehran arms the rebel movement.

Dozens of foreign diplomats have been evacuated from the city as rebels closed in on the city, according to television reports in Saudi Arabia. The country's state TV said on Saturday morning: "The Saudi Royal Navy implemented an operation called Tornado to evacuate dozens of diplomats, including Saudis, from Aden."

Sisi, a former soldier, told the summit that the Arab world was facing unprecedented threats and said the attacks would continue until the Houthis surrender.

The summit comes amid mounting instability and insurgencies in the region. A months-long rebellion by the Houthis has escalated into a regional conflict that threatens to tear apart the impoverished state at the southern tip of the Arabian peninsula.

On Friday night, there were reports that the Saudi-led coalition was continuing its air strikes on Yemen's capital, Sana'a.

Planes also attacked a convoy of Houthi armoured vehicles, tanks and military trucks heading from the coastal town of Shaqra for an attack on Aden, the country's commercial centre.

At least 39 civilians have been killed in the Saudi-led Operation Decisive Storm against the Iranian-backed Houthis and their allies since it began on Thursday, officials at the rebel-controlled health ministry in Sana'a said.

Up to 10 countries, including Egypt, have joined the Saudi coalition as Riyadh leads the predominantly Sunni Muslim 22-member Arab League in a bid to curb the growing regional influence of Iran.

Twelve died when residential areas were hit in a raid on a military base north of the capital, the officials told AFP.

The annual Arab League summit was originally scheduled to discuss a joint Arab military force, but is instead focusing of the Yemen crisis.

The US president, Barack Obama, has said the United States shares a "collective goal" with its regional ally to see stability in the war-torn state, where the Houthis have been tightening their grip since the new year.

He also offered support to King Salman, as it emerged that US military forces had rescued two Saudi pilots forced to eject from their fighter jet in the region on Thursday.

However, Ban Ki-moon, the UN secretary-general, has said negotiations were the only way to prevent a long-term conflict in Yemen.

Also speaking at the summit, Ban said he was angry and shamed by the failure of the world to stop Syria's raging civil war and promised to step up diplomatic efforts.

"Negotiations - facilitated by my special envoy, Jamal Benomar, and endorsed by the security council - remain the only chance to prevent long, drawn-out conflict," he said.