Heavy fighting broke out Thursday in the Somali capital Mogadishu, after government forces backed by African Union troops launched an assault against a stronghold of the hard-line Shebab insurgents, officials and witnesses said.

"There is heavy fighting this morning in several locations, it is too early to say about casualty numbers, but there are some civilians who were injured in the crossfire," said Ali Muse, the head of Mogadishu's ambulance service.

The World Bank on Monday pledged more than $500 million (348 million euros) to aid the drought-stricken Horn of Africa region, as United Nations aid chiefs met in Rome to discuss ramping up relief efforts.

The bulk of the money will go towards long-term projects to aid livestock farmers while $12 million will be for immediate assistance to those worst hit by the crisis and facing starvation, the World Bank said in a statement.

Somalia's newly-appointed women's minister is under house arrest after being abducted by Islamist insurgents, family members said on Friday.

Gunmen seized 32-year-old Asha Osman Aqiil on Thursday in Balad, a town north of the capital Mogadishu, a day after she was named the country's minister for women and family affairs.

Al-Qaida-inspired insurgents abducted and detained Somalia's newly appointed women's minister Thursday while she was on her way to take up office, officials and witnesses told Agence France Presse.

Asha Osman Aqiil was named women and family affairs minister on Wednesday. She was kidnapped by the Shebab fighters in Balad town, some 30 kilometers north of the capital Mogadishu.

Twelve million people in the drought-hit Horn of Africa region need emergency aid, the U.N. food agency said on Wednesday, appealing for $120 million to help desperate farmers.

"Around 12 million people in the Horn of Africa are currently in need of emergency assistance," the Food and Agriculture Organization said in a statement, adding that hundreds of people are dying every day in the crisis.

The United Nations said Wednesday that famine has hit two parts of rebel-held Somalia, due to a severe drought affecting more than 10 million people in the Horn of Africa.

"The United Nations declared today that famine exists in two regions of southern Somalia: southern Bakool, and Lower Shabelle," a statement by the U.N. Office for the Coordination of Humanitarian Affairs for Somalia said.

The plight of millions of people left hungry by a harsh drought across the Horn of Africa is set to worsen, with the rains not expected soon and harvests months away, a top U.N. official warned Saturday.

Scanty or failed rainfall in the region over the past two years has already forced thousands of Somalis to flee their country and ruined the livelihoods of millions in parts of Kenya, Ethiopia and Djibouti.

Many people are dying of hunger while fleeing serious drought in Somalia, the U.N. refugee agency said Friday, warning that aid efforts could be overwhelmed by large numbers of malnourished refugees.

"Many people are dying en route from what we hear," said Melissa Fleming, spokeswoman for the U.N. High Commissioner for Refugees in Geneva.

A U.S. drone fired on two senior commanders of Somalia's Shebab Islamist insurgency after they were found to have ties to al-Qaida, the Washington Post reported late Wednesday, citing U.S. officials.

The strike last week is believed to have wounded the two leading militants and came amid increasing concern among U.S. officials about growing ties between Shebab and the global terror network, the Post said.

Somali President Sharif Sheikh Ahmed on Thursday appointed Abdiweli Mohamed Ali as prime minister, replacing Mohamed Abdullahi Mohamed who resigned under a reconciliation accord.

"He has the personality and the kind of knowledge that makes him fit to become the prime minister," the president said in announcing Ali's appointment.