Mogadishu's police chief has been killed as government forces attacked insurgent bases in the Somali capital.
Witnesses saw the bodies of at least eight people, mainly civilians, in the latest battle to convulse the city.
"This is the strongest fighting we've seen in recent months," one resident, Asha Mo'alim, told the BBC. "We're ducking in our rooms."
Pro-government forces have been locked in fierce battles with radical Islamist guerrillas in the city since 7 May.
In Wednesday's fighting, civilians could be seen running across the streets and sheltering by walls as heavy gunfire shook the Hodan area in south Mogadishu.
Government police spokesman Colonel Abdulahi Hassan Barise said: "The regional police chief, Colonel Ali Said, was among the dead, God bless him."
BBC East Africa correspondent Will Ross says the police chief's death will be a significant setback for the pro-government forces as he had often been on the front line encouraging his colleagues to defend their positions.
Radical Islamist fighters wearing headscarves with ammunition belts draped over their shoulders were seen coming from areas on the outskirts of the capital to join their men in the battle.
In one area, the fighting reportedly sucked in peacekeepers from an African Union base, prompting them to fire tank shells at the rebel strongholds, however AU officials have denied any involvement.
"A mortar landed on my neighbour's house and killed two people and injured four others," said another resident, Abdiwali Dahir.
More than 120,000 people have been displaced by the recent violence
"I have seen the dead bodies of three civilians recognised by the local residents, an Islamist fighter and a government soldier, lying in the street," another resident, Farah Abdi, told the BBC by telephone, with the sound of heavy gunfire echoing in the background.
The latest bout of intense fighting has killed more than 250 people, civilians and combatants since it erupted last month.
More than 120,000 people have been displaced by the violence, according to the United Nations.
A combined force of radical Islamic militants, including al-Shabab, which is accused of links to al-Qaeda, has been trying to topple the fragile UN-backed government for three years.
A moderate Islamist president took office in Somalia in January but even his introduction of Sharia law to the strongly Muslim country has not appeased the guerrillas.
The country has not had an effective national government since 1991.
Some four million people - a third of the population - need food aid, aid agencies say.