The fighting between Somali troops and anti-government fighters killed six civilians earlier in the day, Muse said.

Twenty-one civilians were wounded in the earlier fighting.

Hospital shelling

The Red Cross on Thursday expressed shock at the repeated shelling of a hospital in Mogadishu that killed at least one patient in the past three days.

IN DEPTH


Timeline: Somalia
Restoring Somalia
A long road to stability
Al-Shabab: Somali fighters undeterred
 Somalia at a crossroads
 Somaliland: Africa's isolated state
 What next for Somalia?
 Profile: Sharif Ahmed
 
Who are al-Shabab?
 Riz Khan: The vanishing Somalis

"We are shocked about the situation at Keysaney [hospital]," Pascal Mauchle, head of the International Committee of the Red Cross (ICRC) delegation in Somalia, said in a statement.

"The situation is becoming more and more dangerous for patients and medical staff by the day."

A first shell on Tuesday left one patient dead and another wounded.

According to the ICRC two more mortar shells hit the hospital on Thursday, damaging the building.

Somalia's fragile, UN-backed government, established in 2004, has been battling Islamist fighters who control much of the country's south and centre.

Independence anniversary

The government controls only a few blocks of Mogadishu and relies on African Union peacekeeping troops to protects key government officials and installations.

Somalia has not had a functioning government in nearly 20 years.

Ban Ki-moon, the UN secretary-general, urged Somalis to seek unity in their divided country, which marked its 50th independence anniversary on Thursday.

Somalia gained independence from Italy in 1960 and merged with Somaliland, a British protectorate that proclaimed independence five days earlier.

Somalia has been mired in civil war since 1991.