At least two people have reportedly been killed during heavy fighting in the Somali capital, Mogadishu, as a reconciliation conference is to open.
Witnesses said that insurgents fired mortars into the city’s main market, sparking a fierce army response.
"It was the worst gun battle I have ever heard," said Mohamud Ibrahim. "They used all sorts of weapons."
The conference has been repeatedly postponed, with a boycott by Islamists and Mogadishu’s clan elders.
The BBC’s Mohammed Olad Hassan in Mogadishu says some people have fled the area around Bakara market, where attacks are common.
The conference venue is far away, in north Mogadishu but our reporter says the explosions could be heard there, sparking fears it could be attacked.
Police said one soldier and one civilian died.
Islamists have threatened to attack the conference, reports the AP news agency.
But President Abdullahi Yusuf has said the internationally-backed talks will go ahead even if a nuclear bomb is dropped.
Several mortar shells landed near the venue on Sunday, injuring civilians, when the conference was first opened.
It was immediately postponed to let give some of the more than 1,000 delegates more time to arrive.
The main Islamist opposition have refused to attend, saying the venue is not neutral, while Ethiopian troops remain in the country.
Ethiopia helped government troops oust Islamists from Mogadishu last December.
Somalia has been without a functioning government for 16 years.