The World Food Program says it is exploring “every possibility” to resume working in southern Somalia, after the Islamist militant group al-Shabab said it would welcome aid groups to areas under its control.

In a statement Wednesday, the World Food Program said it is consulting with the United Nations as well as donor countries, and will return to southern Somalia if conditions allow.

The group halted its operations in parts of Somalia last year because of threats and extortion demands from al-Shabab, which is trying to topple the United Nations-backed government and set up a strict Islamic state.

But the militant group said last week that due to one of the worst droughts to hit the Horn of Africa in decades, it will welcome aid groups providing food and other supplies to Somalis.

U.N. Secretary-General Ban Ki-Moon said Tuesday that severe drought in East Africa has caused a “catastrophic” humanitarian crisis that must be dealt with urgently.

He said more than 11 million people need immediate help in order to stay alive.

The drought is affecting several countries and has prompted a mass migration of starving people in Somalia, with many crossing borders to camps in Kenya and Ethiopia.

Al-Shabab rules much of southern and central Somalia, while the government controls only parts of the capital.

However, government and African Union forces have retaken parts of Mogadishu in an offensive that began in February.

Somalia has not had a functioning central government since the fall of dictator Mohamed Siad Barre in 1991.