NAIROBI, Kenya (AP) — Allied African troops have taken full control of Kismayo in Somalia, the last stronghold of Extremist rebels who have been fighting against the country's internationally backed government, a Kenyan military official said Tuesday.

Remnants of the militants, known as al-Shabab, executed seven civilians who did not support them in the southern part of Kismayo on Monday, the Kenyan military said.

Kenya Defense Forces and the Somali National Army are now patrolling the streets of Kismayo, Kenyan military spokesman Maj. Emmanuel Chirchir said through Twitter. He said that the troops had secured the city's central police station and the new airport. He said military aircraft will start landing there.

Kenyan troops invaded the southern Somali city of Kismayo early Friday, and al-Qaida-linked al-Shabab announced soon after that their forces were leaving the lucrative port town.

After years of bloody street-by-street warfare, African Union troops from Uganda and Burundi pushed al-Shabab out of Somalia's capital of Mogadishu in August 2011. The AU troops have since taken over towns outside of Mogadishu as well. Kenyan forces invaded Somalia late last year, and have been moving slowly toward Kismayo.

The once-powerful al-Shabab spent years defending its Mogadishu territory, but since being forced out it has chosen to retreat from towns when challenged by African Union forces or Ethiopian troops who moved into western Somalia earlier this year.

Allied African troops sent by the African Union are helping Somalia's fragile government to restore order to the failed state that has been in chaos since warlords overthrew a longtime dictator in 1991.

Analysts expect that now that al-Shabab has been forced from all of Somalia's major cities, the group will resort to guerrilla tactics such as suicide attacks and roadside bombs. Al-Shabab claimed through Twitter Tuesday that it had set off huge explosions targeting allied troops and killed scores attempting to enter a regional administration building.

But the Kenyan forces disputed al-Shabab's claim. Bomb experts had simply detonated improvised explosive devices planted at the new airport, said Kenyan army spokesman Chirchir.

Residents in Kismayo said a hand grenade had been thrown at a Somalia government vehicle and exploded without causing any casualties.

Claims about fighting in Somalia are difficult to verify.

The Kenyan military also said the Somali National Army arrested an al-Shabab militant who wanted to detonate a bomb targeting the troops. It exploded prematurely and no one was injured.