At least six people are reported to have been killed in the Somali capital Mogadishu, as African Union and government forces battle to protect the flow of food aid against militant attacks.

Witnesses said the deaths occurred during heavy fighting Thursday — one day after the World Food Program airlifted 14 tons of food into Mogadishu.

Government and AU troops appear to be trying to seize ground held by the al-Qaida-linked militant group al-Shabab, which has banned assistance from the U.N. food agency.

A spokesman for AU peacekeepers, Lieutenant Colonel Paddy Ankunda, says the operation aims to ensure that aid agencies can continue to operate and get vital supplies to starving Somalis.

The United Nations reports at least 100,000 Somalis have migrated to Mogadishu recently in search of life-saving food and water.

The U.N. estimates 11 million people in the Horn of Africa need emergency aid, as the region suffers its worst drought in six decades.

The world body has declared a famine in two sections of southern Somalia, both of which are al-Shabab strongholds.

The World Food Program is expected to airlift more aid this week to eastern Ethiopia and northern Kenya, near the Somali border.

Thousands of Somalis are streaming across the border to overcrowded camps in Kenya and Ethiopia.