The Somali militant group al-Shabab says its fighters are still holding hostages inside the Kenyan mall where gunmen began a deadly siege on Saturday.
The group said in a series of Twitter messages Tuesday that militants were "holding their ground" at the Westgate shopping center in Nairobi, and that a "countless" number of dead bodies were inside.
Kenya's military says it is conducting "mop up" operations at the site, while Kenya's police urged people to ignore what it called al-Shabab's "propaganda."
Earlier, officials had said they were in control of the mall with soldiers going through the building looking for anyone still inside, and that all of the hostages had been freed.
Fresh gunfire was heard around dawn Tuesday and again about three hours later.
Al-Shabab also repeated its stated reason for staging the attack, posting Tuesday that "peace will come" to the mall when Kenya removes its forces from Somalia. Kenya has rejected that demand.
Kenyan forces entered neighboring Somalia two years ago to help rout al-Shabab, which has been fighting to turn Somalia into a conservative Islamic state. Al-Shabab militants often crossed the border to stage attacks in Kenya.
Sixty two people have died in the siege that began Saturday when gunmen stormed the busy shopping mall. Gun battles between Kenyan security forces and the militants have killed three of the gunmen and wounded 11 soldiers. Authorities say at least 10 suspects have been arrested.
The dead include nationals from Britain, Canada, China, France, Ghana, India and South Korea.
Kenyan officials say they believe the gunmen include fighters from several nations. Foreign Minister Amina Mohamed told the PBS Newshour that two or three Americans of Somali or Arab origin and a British national took part in the attack.
White House spokesman Ben Rhodes said the U.S. has long been concerned about al-Shabab recruiting Americans to Somalia, and that the government is examining reports they were involved in the mall siege.
U.S. President Barack Obama said he has spoken directly with Kenya's President Uhuru Kenyatta, and will provide whatever law enforcement assistance Kenya needs.
Mr. Obama said he is confident Kenya will rebuild. He called it one of Africa's most stable democracies.
President Kenyatta vows to stand firm against terrorism and punish those behind the attack "swiftly" and "very painfully." The president said his nephew and the young man's fiancee were among those killed.