RESIDENTS fled Somalia's capital yesterday during a lull in fighting between government forces and hardline Islamist insurgents which killed at least 45 people a day earlier.

Government forces launched a pre-dawn offensive on Friday to try to drive Islamist rebels from their Mogadishu strongholds, unleashing the bloodiest day's combat in months.

Sporadic fighting early yesterday tapered off and residents emerged to seek food, or join the estimated 49,000 others who have fled the capital in the past two weeks.

"Large numbers of families started fleeing today from new districts and this will deepen the already worsening humanitarian situation," said Ali Yasin Gedi, vice-chairman of Elman Peace and Human Rights Organisation.

Neighbouring states and Western governments alike fear that Somalia, mired in civil war for 18 years, could become a haven for militants linked to al-Qaeda unless the new government of President Sheikh Sharif Ahmed can defeat them.

Since the start of 2007, fighting has killed at least 17,700 civilians and driven more than one million people from their homes. About three million Somalis are currently surviving on emergency food aid.

More than half of those killed on Friday were civilians and at least 182 people were also wounded in the fierce clashes.

A senior opposition official said the insurgents were giving residents a chance yesterday to leave their homes.

But Sheikh Mohamed Ibrahim added: "We still remain in our positions and we will resume if the government attacks us."

Islamist insurgents took up arms in 2007 to drive out Ethiopian troops propping up a Western-backed government which failed to wield control over much of the Horn of Africa nation.

The Ethiopians withdrew at the start of 2009 and an Islamist president was elected in neighbouring Djibouti in January. However, the insurgents have intensified attacks against the new administration and African Union peacekeepers in Mogadishu.

The hardline al-Shabaab - which Washington says has close ties to al-Qaeda - and Islamist guerrilla group Hizbul Islam have been spearheading attacks on Somalia's capital and the centre of the country.

Somalia's government has accused Eritrea of supporting al-Shabaab fighters with planeloads of weapons, including AK-47 assault rifles and rocket-propelled grenades.

The African Union (AU) stepped up pressure on Eritrea on Friday by calling for United Nations sanctions, a no fly-zone and a sea blockade of Somalia to stem the flow of weapons.

In a statement, the 53-member AU said the UN Security Council should "impose sanctions against all those foreign actors, both within and outside the region, especially Eritrea, providing support to the armed groups".

Eritrea's president denies the allegation of support, saying US agents are spreading lies to blacken his government's name.

Until Friday, pro-government forces had not looked strong enough to break al-Shabaab's grip on parts of Mogadishu.

Last week's defection of a veteran warlord with hundreds of fighters may have prompted Ahmed to order the new offensive.

Experts say pro-government forces will be hard pushed to extend their reach to distant provinces, increasing the risk of protracted fighting in a country that has known little but violence and anarchy since its dictator was ousted in 1991.

An important figure in any reconciliation would be hardline opposition leader Sheikh Hassan Dahir Aweys, who ran Mogadishu and much of southern Somalia alongside Ahmed in late 2006.

The two Islamists - Aweys was always considered the more hardline - split after Ahmed joined the peace process.

"Somalia has no government we recognise," Aweys said in an interview on Friday. "We should not be deceived by Westerners like Sharif. We shall defeat the government soon, God willing."