Kenyan and Somali government troops launched an amphibious assault and captured Somalia’s southern port of Kismayo, the last major stronghold of Islamist al-Shabaab militants, the Kenyan military spokesperson said Friday.

"(A report that) Kismayu fell today to KDF (Kenyan Defense Forces) and TFG (Somali government troops) forces is indeed very true," military spokesman Cyrus Oguna told Kenya's Citizen television, reported Reuters.

However, spokesmen for the al-Qaeda-aligned al-Shabaab group told news agencies that the fighting was going on.

Kenya's military said Thursday that its jets had bombed the airport in Kismayo, destroying an armory and warehouse used by the militants.

The Kenyan troops are part of the African Union’s (AU) Amisom force, which is on a mission to take control of the country from the insurgents for the newly elected U.N.-backed president, Hassan Sheikh Mohamud.

"Kismayo has fallen and with minimum resistance," Oguna told AFP. "It was a joint operation both on air and ground, we finally entered Kismayo at 2:00 am (2300 GMT Thursday).”

"We cannot give casualty figures at the moment; the damage has not been assessed," Oguna told AFP, insisting that Kenyan forces were inside the town.

However, the rebels and the city residents said the government troops were yet to enter the city and that the militants were engaged in heavy fighting with the military at the time of the announcement of the capture.

Oguna told BBC that there were “some parts that still will be under the control of al-Shabab because we only got there a couple of hours ago, and Kismayo is a big city."

The coordinated operation between Kenyan and Somali troops to capture Kismayo began almost a year ago.

Al-Shabaab lost control of Somali capital Mogadishu and several other towns over the past year but much of the countryside in south and central Somalia continues to have a strong militant presence.

According to BBC, Amisom has released a statement saying it had "successfully inserted" troops "to liberate the people of Kismayo to enable them to lead their lives in peace, stability and security.”

It urged "all fighters remaining in Kismayo to lay down their arms."

Some 10,000 people have fled Kismayo in the past week, according to U.N. refugee agency estimates.