Bilal al-Sudani: US forces kill Islamic State Somalia leader in cave complex

US forces have killed an Islamic State leader, Bilal al-Sudani, and 10 of his operatives in northern Somalia, American officials say.

He was killed after US special forces raided a remote mountainous cave complex hoping to capture him.

"Al-Sudani was responsible for fostering the growing presence of ISIS in Africa," Defence Secretary Lloyd Austin said.

He also allegedly funded the group's activities globally, Mr Austin added.

Analysts say the fact that US troops were sent to kill or capture Sudani, rather than using a less risky drone strike, indicates his significance.

In recent years, the Islamic State group has reportedly expanded its activities into several African countries, including Mozambique and the Democratic Republic of Congo.

However Islamic State is a relatively small group in Somalia, with the al-Qaeda linked group al-Shabab far more prominent - it controls many southern areas.

Prior to joining Islamic State, Sudani allegedly did operational work for al-Shabab, assisting with training fighters.

He is accused of playing a "financial role with specialized skills which made him an important target for US counterterrorism action," an anonymous US official told the AFP news agency.

The operation to target Sudani is said to have taken months to plan.

"It's a very positive and welcoming," said Somali government security adviser Hussein Sheikh Ali.

He stressed that Islamic State is not as big a threat as al-Shabab in Somalia, but that Sudani was "dangerous".

"The message is, that the leaders of all terror groups in Somalia are not safe," he continued.

The raid comes less than a week after the US said a drone strike had killed 30 al-Shabab militants.

In recent months, pro-government forces in Somalia have been making progress against al-Shabab.