Suspected jihadists seized the headquarters of the military garrison at Aden airport on Wednesday after killing at least seven soldiers at the base in Yemen's second city, military sources said.

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 Saudi-backed government is based, 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 seven 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.

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

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.

Ground troops of a Saudi-led coalition, which intervened in support of the government in March last year, are based in the city.

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.