A suicide blast at the airport of Somali capital Mogadishu Thursday killed at least 10 people, witnesses said.

Witnesses said they saw a bomber drive up to the main gate, protected by African Union peacekeepers, and then detonate an explosive device in his car when he failed to gain entry.

'Around 10 corpses were lying at the airport gate, including Somali police,' Zakaria Ahmed Salim, who owns a shop by the gate, told DPA. 'The suicide attack was followed by skirmishes between the attackers and peacekeepers.'

The spokesman for the African Union peacekeeping mission AMISOM could not be contacted to establish if peacekeepers were amongst the dead.

Al Qaeda-linked Islamist insurgent group Al Shabaab is in the third week of an offensive aimed at toppling the weak Western-backed government after years of bloody stalemate.

Before the bombing, Somalia's Transitional Federal Government had warned Al Shabaab may be looking to stage a large attack as the Muslim holy month of Ramadan comes to an end.

'We cannot discount the possibility of an Eid spectacular by Al Shabaab to end what has been a fruitless and desperate offensive,' Information Minister Abdirahman Omar Osman said in a statement.

Al Shabaab, backed by foreign militants, has increasingly turned to suicide attacks as a weapon - including twin blasts in the Ugandan capital in July that killed 76.

Ugandan soldiers make up the majority of the African Union peacekeeping forces protecting the Somali government.

The insurgent push coincided with the news that Uganda was sending in more troops to bring the AU force up to its mandated strength of around 8,000.

Prior to Thursday's attack, the UN said more than 230 civilians had died in the latest burst of fighting.

Aid agencies often accuse the government and peacekeepers of indiscriminately shelling civilian areas in response to insurgent mortar attacks.

However, the government claimed that many of the dead civilians could well be insurgents.

'We know we have killed many al-Shabaab terrorists who have attacked us,' Osman said. 'But by the time they reach the hospitals, the bodies have been stripped of weapons, ammunition and other paraphernalia, and they look like ordinary civilians.'

The current insurgency, which has claimed more than 21,000 lives, kicked off in early 2007 following Ethiopia's invasion to topple the ruling Islamist regime.

Somalia has been immersed in chaos since the 1991 ouster of dictator Mohamed Siad Barre.