Kenyan troops say they are closing in on Islamist extremists holding an unknown number of hostages inside a Nairobi shopping mall, in a deadly siege that began on Saturday.
Explosions could be heard and thick black smoke was seen rising above the Westgate mall on Monday.
Kenyan officials say the military controls all the floors of the shopping center and has rescued an unspecified number of hostages. But a number of gunmen are still at large.
The Somali terrorist group al-Shabab has claimed responsibility for the attack. It says it was in retaliation for Kenya's military intervention in Somalia. It demands that all Kenyan forces leave Somalia -- a demand the Kenyan government rejects.
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.
Al-Shabab militants stormed the mall during a busy shopping day Saturday, walking from store to store, shooting down shoppers. They also opened fire on a group of children in a cooking class and murdered people in the parking lot.
Kenyan officials say 62 people were killed along with two gunmen. The Red Cross puts the death toll at 69. Among those killed were nationals from Britain, Canada, China, France, India and South Korea.
Kenyan 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.
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.
The FBI is investigating reports that some Americans who joined al-Shabab were involved in the mall attack.