President Barack Obama took the first step Monday toward providing US military assistance to Somali forces battling Islamist militants, after the easing of a UN arms embargo last month.

Obama signed a determination stating that having the legal capacity to offer defense equipment to Somalia was in the national interest of the United States and could promote peace and stability in East Africa.

The move allows the US Secretary of State to consider the provision of arms to Somalia but does not signal a decision to provide specific assistance, said National Security Council spokeswoman Caitlin Hayden.

"The United States is committed to being a long-term partner in assisting the defense forces in Somalia to become professional military forces," Hayden said.

The UN Security Council last month suspended the arms embargo against Somalia for a year, easing the oldest international weapons blockade to help the government take on Islamist militants.

The 15-member council unanimously passed a resolution allowing light arms to be sold to the Somali armed forces as they seek to rebuild and spread government authority into territory taken from the Al-Qaeda-linked Shebab.

A US official said on condition of anonymity that Obama's decision was not based on any new threat assessment in Somalia.

Since 2007, the United States has provided $133 million in security sector assistance to Somalia, a form of aid designed to help nations build structures to provide for their own security.

The arms embargo was imposed in 1992, a year after the fall of dictator Mohamed Siad Barre, as rival warlords battled for control of the East African nation.

A transitional government, backed by an African force, is starting to establish itself after major victories against the Shebab.

The United States was a key player in pressing for the end of the embargo, in a show of support for President Hassan Sheikh Mohamud.

Shebab are considered to be on the back foot, having lost a string of key towns in recent months to African Union forces, Somali troops and Ethiopian soldiers.

But Washington believes the group remains a threat to stability in the Horn of Africa and beyond. In 2010, Shebab is believed to have been behind suicide bombings in Uganda, and earlier this year claimed to execute a French hostage.