Suspected jihadists seized the army headquarters at Aden airport on Wednesday after killing at least 10 soldiers at the base in Yemen's second city, home to the country's Saudi-backed government.

Troops surrounded the headquarters building where between 15 and 20 of the attackers were believed to be holed up, triggering heavy exchanges of fire through the morning, one military source said.

"We have no news of the officers who were inside the building at the time of attack," the source said.

Security forces in the southern port city, where Yemen's government has taken refuge after rebels seized the capital Sanaa, have come under repeated attack from both the Islamic State group and its jihadist rival Al-Qaeda.

The assailants, who were wearing military uniforms, penetrated the airport garrison after setting off one car bomb at its entrance then ramming through a second and detonating it inside, another military source said.

The twin bombs killed at least 10 soldiers. "The attackers were jihadists," the source said.

Reinforcements were rushed to the airport in the city's Khormaksar district, where they traded rocket-propelled grenade and small arms fire with the militants.

Troops also came under mortar fire from outside the airport perimeter, the source said.

Apache attack helicopters of a Saudi-led military coalition that intervened in support of the government in March last year were in the skies above the base, witnesses said.

Troops closed off access roads to the airport district from outside the city, the witnesses added.

The attack came as Muslims celebrated the feast of Eid al-Fitr which marks the end of the holy fasting month of Ramadan.

 

- Repeated jihadist attacks -

The port city of Aden is under the control of government forces who are struggling to secure it more than a year after it was taken back from Huthi Shiite rebels who have seized control of large parts of the country.

Both Al-Qaeda and IS have exploited the power vacuum created by the conflict between the government and the rebels to expand their presence in the south and southeast.

Last month, CIA director John Brennan told the Senate Intelligence Committee that Al-Qaeda had several thousand "adherents and fighters" in Yemen while there are also "several hundred" fighters loyal to IS.

In May, twin suicide bombings in Aden claimed by IS killed at least 41 people.

A spate of shootings in April and May claimed the lives of the city's traffic police chief and the governor of its main prison, while the chief of police escaped two assassination attempts in the space of a week, one of which killed four of his guards.

Washington considers the Yemen-based Al-Qaeda in the Arabian Peninsula to be the network's deadliest franchise and has vowed no let-up in its longstanding air war against the jihadists.

A US drone attack killed three suspected Al-Qaeda militants in Shabwa province east of Aden on Monday, a security official said. On Friday, a similar drone attack in Shabwa killed four suspected jihadists.

In March this year, the Saudi-led coalition too turned its sights on the jihadists after a year of focusing its firepower on the Huthi rebels and their allies.

Emirati and Saudi special forces helped government forces to recapture the southeastern city of Mukalla from Al-Qaeda in April ending a year of jihadist rule.

But in Mukalla too, the government has struggled to secure the city and there have been repeated deadly reprisal bombings by the jihadists.

In May, bombs claimed by IS killed 47 police. And on June 27, a wave of suicide bombings targeting the army killed 35 people in the port city and provincial capital of some 200,000 people.