SANAA (AFP) - Saudi Arabia, Germany and Italy became the latest countries to withdraw embassy staff from Yemen on Friday as an exodus of foreign diplomats gathered pace due to growing insecurity.

Long on the front line of the war against Al-Qaeda, Yemen has descended into chaos since Shi'ite militiamen, known as Huthis, seized Sanaa in September and ousted the government last week.

Riyadh, Berlin and Rome said they had temporarily closed their missions in the capital Sanaa.

"Due to the deteriorating security and political situation in the Yemeni capital, Saudi Arabia has suspended all embassy operations in Sanaa and evacuated all its staff," said the Saudi foreign ministry.

The United States, Britain and France have rushed to close their embassies over security fears, with US staff destroying top-secret documents and sensitive equipment before pulling out Wednesday.

The Netherlands followed suit the next day.

The Huthis said Western powers had no reason to shut their embassies, insisting security was solid in the capital.

"The situation is anything but stable," said a German foreign ministry spokeswoman, calling the ouster of the government by the Shi'ite militiamen "unacceptable, dangerous and with consequences for the region".

"We decided yesterday to temporarily close the embassy in Sanaa and the personnel departed the country early this morning," she said.

The Italian foreign ministry said: "We hope mediation efforts led by UN envoy Jamal Benomar will create security conditions allowing a return of diplomatic personnel to Yemen as soon as possible".

The latest embassy closures came a day after remarks by UN Secretary-General Ban Ki-moon, who warned Yemen was falling apart.

"Let me be clear: Yemen is collapsing before our eyes. We cannot stand by and watch," Ban told the UN Security Council in New York.

The instability has been seized upon by Al-Qaeda in the Arabian Peninsula (AQAP), which is expanding its foothold across the country.

AQAP fighters overran an army camp in southern Shabwa province on Thursday, that left 12 troops and 15 militants dead, military officials said revising an earlier toll of seven killed.

The militants also seized a large quantity of armour and heavy weaponry, including dozens of tanks and army vehicles as well as artillery pieces, an military official said.

They later handed back control of the camp following tribal mediation but kept the weapons, local government officials said.

UN RESOLUTION DISCUSSED

On Friday, suspected AQAP militants also shot dead an air force pilot in the southern Lahij province, a local government official told AFP.

Since seizing Sanaa, the Huthis have pressed into central and southern provinces and clashed regularly with AQAP and local Sunni tribes.

Last week, they dissolved parliament and declared a "presidential council" after Western-backed leader Abedrabbo Mansour Hadi resigned over what he said was an ungovernable situation.

Ban at the weekend called for Hadi to be fully restored as president, following talks with King Salman in Saudi Arabia, which has described the Huthi power grab as a coup.

UN special envoy Benomar said Yemen had reached "a crossroad".

"Either the country will descend into civil war and disintegration, or the country will find a way to put the transition back on track," Benomar told the Security Council by video link from Sanaa.

Following closed-door consultations in New York, Britain said it would work with Jordan on a resolution to outline the Security Council's stance on Yemen.