Somali Islamists are letting civilians in drought-hit regions under their control move with relative freedom to find food, the group and a U.N. official said on Thursday, but they are continuing to restrict the access of international aid groups.

Somalia, struggling to recover from more than 25 years of civil war and an ongoing battle between its U.N.-backed government and Islamist insurgents, could sink into famine if the April rains fail.

About quarter of a million people died during the last famine in 2011, when al-Shabab's restrictions on movement and its refusal to allow many aid groups access pushed up the death toll, aid groups say.