Several explosions have rocked Somalia's southern port city of Kismayo as Kenyan and Somali troops take control of what has been the last bastion of the rebel group al-Shabab.
Al Jazeera's Peter Greste, reporting from Kenya's capital Nairobi, said up to three explosions went off on Tuesday, with the African Union Mission in Africa (AMISOM), the peacekeepers in Somalia, claiming to have carried out two controlled explosions near the airport.
"The third blast took place at the Kismayo administrative building known locally as the "K2" building," our correspondent said.
"According to AMISOM sources, there were no casualties. An AMISOM spokesman says the bomb was a remote-controlled device, and the attacker has been apprehended.
"Al Shabab says it carried out the attack at the K2 office, and says that scores were killed and injured. An al-Shabab spokesman said the improvised explosive device (IED) was aimed at Somali troops trying to enter the building."
Kenyan and Somali troops, fighting under the banner of AU troops, entered Kismayo on Tuesday and were reported to be in control of strategic points in the city.
A Kenyan military spokesman, Major Emmanuel Chirchir, said through the social networking site Twitter that Kenyan troops and the Somali National Army were patrolling the streets of Kismayo,
The troops moved in after al-Shabab fighters withdrew on Friday, following an earlier Kenyan and Somali air, sea and ground assault.
"Nobody really anticipated that there would be no problem, no resistance from al-Shabab inside Kismayo. Al-Shabab has had a long time to prepare for this, likely they have bombs and other devices throughout the city [...] the question is how long Al-Shabab has the capacity to maintain it," reported Al Jazeera's Greste.
Witnesses said that the streets of Kismayo remained largely deserted, and businesses were closed.
"We pray their arrival will not bring chaos and robbery as happened in other towns. We have actually suffered a lot," Mohamed Hashi, a resident in the town, told the Associated Press news agency by telephone.
"Some people are happy to welcome them because they were fed up with the misrule of the al-Shabab fighters," another resident, Abdullahi Farey Hassan, told the AFP news agency.
"But I will have my reservations until I see them doing something good. I hope they will be better than al-Shabab."
Kenyan troops had been maintaining their positions outside the city until moving in on Tuesday. They had been occupying positions about five kilometres from the city since launching their assault on Friday.
The Kenyan Defence Forces said on its Twitter feed on Monday afternoon that African Union, Kenyan and Somali troops were "consolidating the gains in Kismayo and expanding out to the rest of the city".
The Kenyan military said that civilian safety and security was a top priority.
Speaking to Al Jazeera, al-Shabab commanders termed the withdrawal on Saturday a "tactical retreat" in order to avoid conflict in the streets, but said that their group had not abandoned the town, and would continue fighting for it.
The rebel group said its fighters were poised to engage the allied troops once they entered the city centre, threatening to turn the streets into a "battlefield".
Members of the African Union Mission in Somalia (AMISOM), which totals 17,000 soldiers across the country, have been cautious about pouring into the port city from its outskirts.
The Somali government had earlier said that it would not enter the city until peace negotiations with local clan leaders had been completed.
On Monday, Hassan Sheikh Mohamud, the newly elected Somali president, praised AMISOM for forcing al-Shabab to vacate the city.
"We believe that this will help to bring about a return to stability in Somalia, and reduce over time the terrorist threat to Somalia and neighbouring states"
- Johnnie Carson,
Senior US diplomat for Africa
"We commend AMISOM and the Somali troops who have shown bravery by forcing the enemy out of the town," a statement from the president's office said.
The United States has also praised AMISOM on its operations to take the city.
"We applaud the work of AMISOM and what they have done in helping to degrade and defeat and push al-Shabab out of Somalia's main cities," said Johnnie Carson, the top US diplomat for Africa, on Monday.
"We believe that this will help to bring about a return to stability in Somalia, and reduce over time the terrorist threat to Somalia and neighbouring states."
Carson called Somalia "a good news story for the region", pointing to the nation's new constitution and newly elected parliament and president, after years of lawlessness.
Kismayo was al-Shabab's last stronghold in the country, and the taxes it levied on goods coming into the port helped to fund the rebellion against the Somali government.
The African Union force is made up of Ugandan and Burundian troops, who pushed al-Shabab out of Mogadishu in August 2011, and forces from Djibouti and Kenya. Carson said troops from Sierra Leone would arrive in Somalia on Monday and Tuesday to bolster AMISOM.