Abdullahi Yare, one of the seven leaders named by the US on its most-wanted list in 2012, was believed to be next in line to take over the leadership from ailing Al Shabaab chief Ahmed Diriye.
The Somali government has announced a top Al Shabaab terrorist, who had a $3 million US bounty on his head, has been killed in a joint air strike in southern Somalia.
The drone strike on October 1, launched by the Somali army and international security partners, killed Abdullahi Yare near the coastal town of Haramka, the ministry of information said in a statement dated Sunday but posted online on Monday.
"This leader... was the head preacher of the group and one of the most notorious members of the Shabab group," it said.
"He was former head of the Shura council and the group's director for finances," the ministry said, referring to a powerful consultation body within Al Shabaab.
A co-founder of the Al Qaeda-linked group, Yare was believed to be next in line to take over the leadership of the movement from its ailing chief Ahmed Diriye, according to the ministry.
"His elimination is like a thorn removed from Somalia as a nation," the ministry said.
Yare was one of seven leaders named by the United States on its most-wanted list in 2012. Washington offered three million dollars for his capture.
The announcement of the strike comes weeks after Somalia's recently elected President Hassan Sheikh Mohamud vowed to stage all-out war on the militants, following a string of deadly attacks. They include a 30-hour hotel siege in the capital, Mogadishu, that killed 21 people.
Mohamud last month urged citizens to stay away from areas controlled by Al Shabaab as he vowed to ratchet up offensives against the terrorists.
US forces have in the past partnered with African Union soldiers and Somali troops in counterterrorism operations, and have conducted frequent raids and drone strikes on Al Shabaab training camps throughout Somalia.
Last month, the US military said it had killed 27 militants in an air strike near Bulobarde, the main town on the road linking Mogadishu to Beledweyne, a key city on the border with Ethiopia.
It said the air strike was carried out "at the request" of the Somali government.
Al Shabaab has waged a bloody insurrection against the Mogadishu government for 15 years and remains a potent force despite an African Union operation against the group.
Its fighters were ousted from the capital in 2011 but they continue to stage attacks on military, government and civilian targets.
The group last week claimed responsibility for a bomb blast that killed a top Somali police officer near the Al Shabaab-controlled village of Bursa, some 30 kilometres north of Mogadishu.