Smoke rises from a government building in Al-Houta, provincial capital of Yemen's Lahej province. 

AFP/Aden

The Shia Houthi militia and its allies on Sunday seized the airport in the strategic Yemeni city of Taez from forces loyal to President Abedrabbo Mansour Hadi, security sources said.

Taez is located in central Yemen on the road between Sanaa, which the Houthis overran in September, and the southern city of Aden, to which Hadi fled last month after escaping house arrest in the capital.

Control of the city would enable the Houthis and forces loyal to former president Ali Abdullah Saleh, who was driven out in early 2012 after a year of bloody protests, to tighten the noose on Hadi.

Some 300 men, including  Houthi fighters dressed in military uniforms and so-called special forces have deployed at the airport as reinforcements continued to arrive from Sanaa by air and land, the source said.

The special forces, previously known as the central security force, is a unit seen as close to Saleh.

"These soldiers are partisans of the former president Saleh," a military source told AFP.

 Houthi militiamen also patrolled certain neighbourhoods of the city and expanded further south by setting up checkpoints in Raheda, some 80 kilometres south of Taez on the road to Aden, security sources said.

 Houthi reinforcements began arriving in Taez on Saturday, a day after multiple suicide bombings that targeted  Houthi mosques in Sanaa killed 142 people and wounded 351. The attacks were claimed by the Islamic State jihadist group.

On the other side, troops loyal to Hadi and southern paramilitary forces have deployed in Lahj province, north of Aden, in anticipation of a possible advance by Houthis, a military source said.

Hadi has been trying to cement his power base in Aden which he declared temporary capital after he retracted a resignation tendered under Houthi pressure.

On Thursday, his forces overran the base of special forces in Aden after its commander refused Hadi's decision to remove him.

US evacuates staff from Yemen

The US said it had evacuated all its staff from Yemen, whose embattled president has appealed for "urgent intervention" by the UN Security Council as attacks by Houthi rebels bring his country nearer to civil war.

"Due to the deteriorating security situation in Yemen, the US government has temporarily relocated its remaining personnel out of Yemen," State Department spokesman Jeff Rathke said in a statement.

The UN Security Council is to hold an emergency meeting on Sunday following Hadi's appeal.

In his letter to the Council, Hadi denounced "the criminal acts of the Houthi militias and their allies," saying they "not only threaten peace in Yemen but the regional and international peace and security."

"I urge for your urgent intervention in all available means to stop this aggression that is aimed at undermining the legitimate authority, the fragmentation of Yemen and its peace and stability," Hadi wrote.

The country is now on the brink of civil war, with a deepening political impasse and an increasingly explicit territorial division along sectarian lines, with rising violence between the Houthi and Sunni tribes and Al-Qaeda.