Smoke rises over the Westgate shopping center after an explosion in Nairobi on Monday.2013 AFP
A loud burst of gunfire was reported to have been heard coming from inside Nairobi's Westgate mall, where police have been carrying out a final sweep of the shops after the last of the hostages had been rescued.
Kenyan special forces are still battling "one or two" al-Shabab fighters believed to be inside Nairobi's Westgate shopping mall, security sources involved in the operation said on Tuesday.
Overnight silence outside the mall was broken at daybreak, following a loud burst of sporadic gunfire, suggesting that the complex had not yet been secured.
The sources said the fighters were located and isolated on one of the upper floors of the complex.
Renewed fighting follows Monday evening's announcement from Kenya's Interior Ministry that troops were "in control" of the Westgate shopping mall in Nairobi, and it believed all hostages had been freed after a deadly siege that killed at least 62 people and injured at least 175.
"Our forces are combing the mall floor by floor looking for anyone left behind," a tweet from the Interior Ministry said. "We believe all hostages have been released.”
That tweet came minutes after the ministry announced, "We're in control of Westgate."
Kenya's Foreign Minister Amina Mohamed told PBS Newshour that a few of the attackers had come from the U.S., specifically from Minnesota and Missouri.
Earlier Monday, gunshots could be heard and black smoke was seen rising from the upscale shopping center.
Three al-Shabab fighters have been confirmed killed in the government raid at the mall, Kenya's Interior Secretary Ole Lenku said Monday.
"We don't want to give you a definitive position on when we think the process will come to an end, but we are doing anything reasonably possible -- cautiously though -- to bring this process to an end," he said at a news conference.
Lenku said that a fire inside the mall was the work of the fighters and that it would soon be extinguished.
He added that the militants included individuals from a number of countries, that some of the attackers -- all of whom are men -- were dressed as women and that the number of hostages was uncertain.
But later Monday, Mohamed, the Kenyan foreign minister, told Al Jazeera's James Bays that about 20 men and women were behind the attack.
Meanwhile in Washington, President Barack Obama called the Nairobi attacks a "terrible outrage" and pledged that the U.S. would give the Kenyan government its full support and cooperation.
Television images Monday showed troops in camouflage running to new positions and an armored personal carrier shifting position.
Kenyan forces continued to bring hostages out of the shopping complex as they kept "closing in" on attackers, according to police inspector general David Kimaiyo. Monday's actions signal the latest push by government troops to end the standoff, now in its third day.
While the number of dead and injured is disputed, the Kenyan government says at least 62 people have been killed in the attack, with scores more wounded.
The Somali militant group al-Shabab claimed responsibility for the attack. Ten to 15 armed fighters are believed to be still in the building.
The attack, which targeted a mall popular with Westerners as well as Kenyans, could prove a major setback for Kenya, a nation that relies heavily on tourism.
The dead included children and several foreigners, including renowned Ghanaian poet Kofi Awoonor. At least three British nationals were among those killed, British Foreign Secretary William Hague confirmed Sunday.
The wounded range in age from 2 to 78. Many victims were at a cooking competition when assailants stormed in with automatic rifles and grenades, witnesses said.
Kenyan President Uhuru Kenyatta, facing his first major security challenge since his election in March, said security forces were engaged in a "delicate operation." He added, "Our top priority remains to safeguard the lives of innocent people held up in this unfortunate incident."
Kenyatta said shooting continued for several hours after the attack began shortly after noon on Saturday but had become tensely calm by that evening.
On Sunday, in an apparent bid to end the standoff, Kenyan forces entered the mall, some carrying rocket-propelled grenades. Meanwhile, helicopters hovered above. Sporadic gunfire was heard throughout the day.
Israeli security advisers were said to be aiding the operation, with an Israeli source telling Reuters that they were helping with the "negotiating strategy" to end the siege.
Kenyan security forces have arrested one of the gunmen who stormed the Westgate complex, Kenyatta said on Twitter. The Kenyan interior ministry said the upper floors of the four-story mall had been secured and that the attackers had been isolated somewhere on the ground floor or in the basement.
Al-Shabab claimed responsibility for the attack in messages posted on its purported Twitter account, stating that the assault was a response to Kenyan troops' being in Somalia. On Sunday, Kenyatta said a probe was under way to confirm who was behind the attack.
Al-Shabab 'holding ground'
The French government confirmed that two of its citizens were killed in what President Francois Hollande described as a "cowardly attack.”
The U.S. government reported an undisclosed number of Americans injured. President Barack Obama phoned Kenyatta Sunday to express his condolences and pledge support for Kenya's "efforts to bring the perpetrators of the attack to justice."
A member of Canada's foreign service and a Vancouver businessman were also among those killed, according to The Globe and Mail.
The United Nations Security Council condemned the attack "in the strongest possible terms" and reminded Kenya that any response must comply with international human-rights laws.
On its purported Twitter account, al-Shabab said there would be no negotiations with Kenyan officials.
"We'll not negotiate with the Kenyan govt as long as forces are invading our country, so reap the bitter fruits of your harvest," the group wrote.
Kenyan troops have been fighting al-Shabab in Somalia, where the anti-government group is seeking to impose Islamic law and has carried out numerous attacks.
Kenya has been hit by a spate of attacks, including explosions of hand grenades and bombs, since it sent troops to southern Somalia in late 2011 to attack al-Shabab bases.
Call for unity
"The border between Kenya and Somalia is very, very porous, and it's very difficult for authorities to control movement across the border," said Al Jazeera's Peter Greste, reporting from Nairobi.
"There's also a very difficult relationship between Somali communities here and the security services. Neither of them trusts the other," he said.
In a live television statement late on Saturday, Kenyatta said the country had "overcome terrorist attacks before" and vowed to "hunt down the perpetrators wherever they run to."
"In fact, we have fought courageously and defeated them within and outside our borders. We will defeat them again," he said.
Asked Sunday if he would pull troops from Somalia, he replied that Kenya would "not relent on the war on terror."
Earlier, Kenyatta confirmed that his nephew and his nephew's fiancée were killed in the attack.
Al Jazeera and wire services