A leader of Somalia's al-Shabab with a $3m bounty on his head has announced he is leaving the armed group.

Zakariya Ismail Hersi, who was al-Shabab's intelligence chief, also renounced the violence carried out by the group and called for reconciliation while speaking to the media on Tuesday.

Hersi made the comments during his first public appearance since his surrender to Somali authorities in late December.

"I can confirm that as of today I am no longer a member of Al-Shabab and I have renounced violence as a means of resolving conflict and I will aim to achieve my goals towards peaceful means, and through reconciliation and understanding," Hersi said.

He spoke to reporters from the information ministry in the capital Mogadishu, where he appeared without guards, according to the AFP news agency.

Some analysts say Hersi defected because he feared for his life due to friction with colleagues loyal to Ahmed Godane, the group's leader who was killed by a US air strike last year, the Associated Press news agency reported.

It is not clear if he will face trial, but Somalia's government said in a statement that it had offered surrendering fighters the "opportunity to reintegrate with Somali society, and guarantees their safety".

It added that it hoped Hersi's surrender would "inspire others to follow his example and join the peace process".

Revenge attacks

Hersi is one of seven top al-Shabab leaders targeted by the Obama administration in 2012 which offered rewards totalling $33m for information leading to their capture.

It is not clear who, if anyone, will get the bounty for Hersi.

Al-Shabab is fighting to overthrow Somalia's Western-backed government, but has also carried out a string of revenge attacks in neighbouring nations.  

The group is blamed for deadly attacks in Somalia and in neighbouring Kenya, whose army is part of the African Union troops bolstering Somalia's weak UN-backed government.

Last week, three Somali nationals were killed when a suicide bomber detonated a car bomb outside a hotel housing the advance party of the Turkish President Recep Tayyip Erdogan who visited the country days later.