The United States says aid workers will not be prosecuted if they deliver food to parts of Somalia controlled by militant group al-Shabab.

Senior Obama administration officials said Tuesday that they are issuing new guidelines in hopes of increasing aid to the drought- and famine-stricken country.

U.S. sanctions make it a crime to provide any support to al-Shabab, which is trying to overthrow the Somali government. Some aid groups have expressed concern they could face prosecution in the U.S. if they work with the group while trying to help starving Somalis.

The Obama administration officials said al-Shabab has diverted some food aid and extorted money from relief groups.

One said that aid agencies must have a “common set of standards” not to pay taxes and tolls to the militant group.

International aid groups are rushing to assist an estimated 3.7 million Somalis affected by the drought, many of them children.

The U.N. says more than 12 million in all across the Horn of Africa are in need of aid, and has issued an appeal for $1.4 billion.

Earlier Tuesday, British relief agency Oxfam said governments and donors need to fulfill their pledges of aid more quickly. The African Union has announced it will hold a donor summit in Addis Ababa next week.

The United Nations recently declared a famine in two regions of southern Somalia, and has warned that famine conditions could spread to other areas.

The drought has forced hundreds of thousands of Somalis to flee their homes in search of food and water. Many have gone to camps in Mogadishu, while others have fled to crowded refugee camps in Kenya or Ethiopia.