In an audio message posted on a pro-Al-Shabaab website, Al-Zawahiri encouraged the militant group who recently lost the port city of Kismayo to Kenyan troops not to be demoralized by the take over and urged them to continue fighting foreign troops in the country.

He said the militants should make these troops to taste what he called “the fire of jihad and its heat” by pursuing them with guerrilla warfare, ambushes and suicide bombings.

The Al-Qaeda leader said Kenyan troops were backed by several allies including the U.S, claiming that the African Union has already been defeated.

In his message, Al-Zawahiri also claimed that American troops were forced to leave Iraq and Afghanistan as well as their operations in Yemen, Libya and Egypt.

The Al-Shabaab, a group which has been battling the UN-backed government in Somalia and proclaims allegiance to Al-Qaeda, has in recent months suffered several major setbacks.

The group once controlled up to 80 per cent of southern and central Somalia and the recent African Union offensive dashed their hopes of taking power.

On Saturday, two suicide bombers attacked a Mogadishu restaurant popular with former exiles, killing two people and wounding several others.