Ethiopian troops will remain in Somalia until African Union forces fighting Islamists can take over, Prime Minister Hailemariam Desalegn said Wednesday, as he met with his Somali counterpart.

"We are waiting for AMISOM (African Union Mission in Somalia) force to come and replace us, and until we get that assurance then we will be waiting there," he told reporters.

Hailemariam, speaking alongside newly elected Somali President Hassan Sheikh Mohamud, on his first official visit to the Ethiopian capital, gave no timeline for a pull out of troops.

Mohamud said that the Shebab is "literally defeated" -- although many experts say it remains a potent threat -- and also warned foreign fighters with the extremists to leave Somalia.

"We have no relationship, and we do not intend to have one, with the foreign fighters in Somalia," Mohamud said. "The only option for them is to leave the country."

Ethiopian troops and tanks invaded Somalia in November 2011 to attack Al-Qaeda linked Shebab insurgents, capturing key towns including Baidoa.

At the same time, anti-Shehab Somali forces and a 17,000-strong AU force have been also battling the Islamists, and are seeking to link up with areas held by Ethiopia.

Addis Ababa -- long seen as a traditional enemy of Somalia -- is a controversial presence in Somalia. Ethiopia entered Somalia in a 2006 US-backed invasion, but was driven out three years later by a bitter insurgency.

War-torn Somalia has been in chaos since the fall of President Siad Barre in 1991.