Nairobi, Kenya - Militias in Somalia are looting shipments of aid for drought victims and forcing aid drivers to pay bribes, the United Nations said on Tuesday.

Attacks by Somali pirates in recent months have caused aid agencies to start transporting relief supplies over land and the convoys have been subjected to pillaging by gun-toting militias at hundreds of road blocks across the country.

"We need across the board support and commitment of everyone to ensure access and protection so that we can alleviate the suffering of Somalis," Maxwell Gaylard, the UN humanitarian coordinator for Somalia, said in a statement.

"We cannot do so if the food convoys, medical supplies and other critically needed assistance are targeted by opportunists and so called uncontrolled militiamen," he added.