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.