A week of fierce fighting in Somalia's capital, Mogadishu, has refugees on the move again.

The United Nation's refugee agency has described the latest fighting as some of the heaviest seen in Mogadishu this year. More than 100 people have been killed and thousands have fled their homes.

The UN Security Council on Friday condemned the upsurge in violence between soldiers for the transitional government and fighters for Islamist militias.

The United Nations High Commissioner for Refugees (UNHCR) said about 30,000 people have fled the city because of the latest round of fighting.

UNHCR spokesman William Spindler said hospitals in central Mogadishu are overwhelmed by the large number of casualties.

Spindler said many of the newly displaced are heading for an area that already shelters more than 400,000 Somalis who fled previous bouts of government and rebel fighting.