Heavy fighting in Somalia has left at least 21 people dead and 30 injured, officials and residents have said.
Islamist insurgents clashed with government forces and their Ethiopian allies in the capital, Mogadishu, and near Mataban, in central Somalia.
The exchanges of machine gun and mortar fire in the capital were the heaviest for two months, a BBC reporter said.
Somalia's government signed a ceasefire pact with opposition groups last month, but some factions rejected the deal.
Islamists linked to the Union of Islamic Courts (UIC) have been staging an insurgency against the government troops and their Ethiopian allies who ousted them from power in 2006.
The BBC's Mohammad Olad Hassan in Mogadishu said the latest violence in the capital began when Islamist insurgents attacked a government military base south of the city.
Civilians killed
At least 12 people were killed, according to security and hospital officials, and witness accounts.
"A mortar landed on house next to us killing a mother and two of her kids and wounded three others from the same family," said one resident in south Mogadishu.
There was also heavy fighting in the centre of the country where insurgents attacked a convoy of Ethiopian troops, our reporter says.
A UIC spokesman said six of his men had been killed in the attack. He said the insurgents had killed some Ethiopian soldiers and destroyed several of their vehicles.
Last month, the Alliance for the Re-Liberation of Somalia signed a three-month ceasefire pact with the government that provided for Ethiopian troops leaving the country within 120 days.
It was signed by a top Islamist leader, Sheikh Sharif Sheikh Ahmed, and Prime Minister Nur Adde.
But another prominent Islamist leader, Sheikh Hassan Dahir Aweys, said insurgents should continue fighting until all Ethiopian troops had left the country.
The renewed fighting came after at least four local aid workers were kidnapped on Monday near Mogadishu.
It was the latest in a series of kidnappings of humanitarian workers that correspondents say are hindering aid operations in a country where many people desperately need food and shelter.
Somalia has experienced almost constant civil conflict since the collapse of Mohamed Siad Barre's regime in January 1991.
The UN has warned that nearly half of Somalia's population is likely to require aid later this year.