Mohammed Nasser Ali, right, pictured in a meeting in June, has escaped death for the second time in a month [AFP]

Yemen's defence minister has survived an attack on his convoy in the southern city of Aden, officials said.

One official said that a suicide bomber drove a car full of explosives into Defence Minister Mohammed Nasser Ali's convoy and other attackers on motorbikes threw hand grenades.

Tuesday's blast in Aden wounded seven soldiers travelling in the lead vehicle of the ministerial motorcade, but Ali, who was riding in the second car, was unharmed, a local official said.

It was not immediately clear who carried out the attack.

'Al-Qaeda tactics'

Investigators found the body of a 19-year-old inside the car which exploded and concluded he was the bomber.

For more on Yemen, visit our Spotlight page

A security official said the attack was consistent with al-Qaeda's tactics.

It was the second time in a month that the defence minister narrowly escaped a bid on his life. 

In August, his convoy hit a landmine in the flashpoint province of Abyan, where al-Qaeda-linked fighters have seized several cities in the coastal province.

Since popular protests against President Ali Abdullah Saleh broke out in this impoverished Arabian Peninsula state earlier this year, fighters suspected of links to al-Qaeda have tightened their grip on the south and have repeatedly targeted troops and security officials.

International powers fear growing lawlessness in Yemen could embolden al-Qaeda's local wing and imperil strategic shipping routes.

Aden lies close to the Bab al-Mandab strait, through which some three million barrels of oil pass daily.