Witnesses in Somalia's capital say at least 14 people have been killed in fierce fighting near the country's presidential palace.
Mogadishu residents say the Islamist militant group al-Shabab tried to advance on the palace overnight Sunday but was stopped by government troops and African Union peacekeepers.
Al-Shabab attacked other government positions on Friday and Saturday. Reports from the city say the group appears to have seized new areas.
Sunday's fighting was centered in Mogadishu's Bondere and Shibis neighborhoods. Witnesses say the sides exchanged gunfire and mortar shells. Dozens of people were wounded in addition to those killed.
Somali President Sheikh Sharif Sheikh Ahmed is currently in Istanbul for a U.N.-backed conference on boosting support for his transitional government.
On Saturday, U.N. Secretary-General Ban Ki-moon said international support for the government is the only way to stabilize Somalia.
Al-Shabab and another militant group, Hizbul Islam, already control much of central and southern Somalia, and large parts of Mogadishu. The government controls only small areas around the airport, seaport and presidential palace with the support of the AU troops.
The Sharif government has struggled with internal conflicts that often hamper its effectiveness.
The president spent much of last week embroiled in a political dispute after he tried to dismiss the prime minister. The president backed down on Thursday, saying he recognized the method of the firing was unconstitutional.
Fighting in Somalia has killed tens of thousands of people and displaced more than a million people over the past few years. Aid groups say the country's humanitarian situation is among the most dire in the world.
The Horn of Africa country has not had a stable central government in nearly 20 years.
Some information for this report was provided by AFP and Reuters.