Mogadishu's recent pandemonium has sparked a civilian exodus
Somalia's president has appealed to Islamist insurgents to negotiate as intermittent fighting continued for an eighth day in the capital, Mogadishu.
Sheikh Sharif Sheikh Ahmed told the BBC the clashes were displacing thousands of the city's residents each day.
But his former ally and Islamist spiritual leader Sheikh Hassan Dahir Aweys rejected his overture.
He told the BBC talks were not possible while African Union troops were in the city where they are guarding key sites.
The United Nations refugee agency says about 30,000 people have been forced from their homes in the last week.
It is estimated more than 100 lives have been lost since a combined force of militant Islamic groups - al-Shabab and Hisbul-Islam, which are accused of links with al-Qaeda - launched their offensive.
AFRICAN UNION IN MOGADISHU
AU force in Somalia (Amisom) was mandated in January 2007
Supposed to be 8,000-strong but currently has only 4,300 troops
Comprised of soldiers from Uganda and Burundi
Sierra Leone has offered battalion, which would take force over 5,000
Restricted by security situation to operations in Mogadishu
Another prominent Islamist leader, Omar Iman Abou Bakr, told the BBC most government soldiers had fled, and those remaining were being protected by soldiers from the African Union.
The 4,300 AU peacekeepers, in the capital to bolster the government, do not have the mandate to pursue the insurgents.
President Ahmed, a moderate Islamist, was elected as president by MPs as part of a UN-backed peace initiative in January.
But even his introduction of Sharia law to the strongly Muslim country has not appeased the guerrillas.
"They see it lawful to shed blood. They aim to take over Somalia by force. We call on them to end the conflict by negotiating on our political differences," the president said on the BBC's Somali Service.
"Somalis are Muslims," he said.
Mr Aweys, however, accused him and his government of being unelected and unrepresentative.
"This government and parliament are not acceptable to Somalis, they did elect them," he said on the same programme.
"Our position is, whether they claim to be a government or not, first the enemy [AU troops] should leave."
"After that all stakeholders should come together and establish something acceptable to all."
But AU envoy Nicholas Bwakira said AU peacekeepers would not pull out of the country.
"It would be unacceptable that Shabab/al-Qaeda take over government in Somalia. This is a group of war criminals," he said.
"There are several members of al-Qaeda, 300 to 400 who are training the Shabab. They have also received heavy armaments from outside. They have received support logistically, financially. We are aware of that," he told the BBC's Focus on Africa programme.
But the UN envoy to Somalia, Ahmed Ould Abdallah said he wanted Somali Islamists - such as Mr Aweys - removed from both the UN and US terror lists, to help dialogue.
"No-one who is on the UN Security Council list of terrorists can be president, or prime minister, because he cannot sit in an office. Even travelling... he can be in trouble," he said in Nairobi.
"Those who are on the US list, we are ready to lobby for them."
It is estimated that more than 16,000 civilians have been killed by fighting since the start of 2007 and more than one million are internal refugees.