The commander of African Union troops in Somalia said Thursday the continent would celebrate if the death of the chief of extremist Shebab rebels in a US missile strike was true.

General Silas Ntigurirwa, commander of the 22,000-strong AU force (AMISOM), said the killing of the feared Islamist chief Ahmed Abdi Godane -- if confirmed -- would be a "proud and happy moment for all Africa".

The fate of Godane remains unclear, three days after a US missile strike targeted his convoy. His death would be a major blow for the Islamists.

Security sources have said there is a "very strong probability" he has been killed, but Shebab officials have so far refused to confirm or deny the reports.

An AMISOM source told AFP Godane "probably died during the attack" but that efforts to verify his death were continuing.

The Shebab are fighting to topple Somalia's internationally-backed government and regularly launch attacks against state targets, as well as in neighbouring countries that contribute to an African Union force.

That included last year's siege of the Westgate shopping mall in Nairobi, which left at least 67 dead.

The air raid came days after African Union troops and Somali government forces launched "Operation Indian Ocean", a major offensive aimed at seizing key ports from the Shebab and cutting off one of their key sources of revenue: multi-million dollar exports of charcoal.

AU forces were targeting Shebab on several fronts, with Ugandan troops leading the offensives against the main port of Barawe, south of Mogadishu.

"Hopefully soon we'll liberate the port towns that allow them to replenish their stocks of weapons and recruit foreign fighters," said Ntigurirwa, speaking to reporters while in his home nation of Burundi.

"Taking Barawe, I think, it'll be very soon."

Washington has carried out a series of drone missile strikes in the past, including attacks reportedly targeting Godane.

Godane, 37, who reportedly trained in Afghanistan with the Taliban, took over the leadership of the Shebab in 2008 after then chief Adan Hashi Ayro was killed by a US missile strike.