President Donald Trump has granted the US military more authority to go after al Qaida-linked militants in Somalia, approving a Pentagon request to allow more aggressive air strikes, officials said.
Mr Trump's decision, which was made on Wednesday but not immediately announced, allows US special operations forces to accompany Somali National Army troops and other African allies as they move closer to the fight, enabling them to call in offensive air strikes quicker.
Portions of southern Somalia, excluding the capital Mogadishu, will be considered a warzone, officials said. That designation gives US forces on the ground the authority to call in offensive air strikes, rather than waiting for approval by higher level commanders.
In a statement on Thursday, Navy Captain Jeff Davis, a Pentagon spokesman, said the additional US support will help "increase pressure on al-Shabab and reduce the risk to our partner forces when they conduct operations".
Somalia has been without a truly functioning government for two-and-a-half decades, its vast ungoverned spaces allowing extremist groups to gather and train. Al-Shabab has carried out deadly attacks in Mogadishu and elsewhere. Attacks on military bases in the past two years have slowed joint African Union-Somali offensives against the group.
General Thomas Waldhauser, the head of US Africa Command, told members of Congress last week he would not turn Somalia into a "free fire zone". He stressed the need for "more flexibility, a little bit more timeliness, in terms of decision-making process" to strike al-Shabab and weaken it.
He dismissed suggestions the change could cause more civilian casualties
The new guidelines pertain to US assistance of Somali and African Union troops, not unilateral American missions in the Horn of Africa country.
About 50 US commandos have been rotating in and out of Somalia to advise and assist local troops. That number could now increase slightly at certain times, said officials.
Somalia is grappling with a devastating famine that has uprooted citizens around the country. The movement of so many people around the battlefield in search of food and water could make strikes more challenging, but the military says it has been preparing appropriately.
There have been no changes to ease rules of engagement or allow for possibility of greater civilian casualties, military officials said. Faster military decisions run that risk, but much of the area now considered a warzone is sparsely populated.
Rules for air strikes in other areas of Somalia have not changed, the officials said.