Officials in Mali say at least four gunmen who shouted Islamic phrases while raiding a luxury hotel in the capital Friday have killed three of their 170 hostages.
Authorities say about 20 hostages have been released, with some of them being taken away in ambulances. Earlier reports said the gunmen released hostages who were able to recite the Quran.
Some media organizations are reporting that at least 134 people and 13 hotel workers are being held hostage by the assailants.
Officials said U.N. and Malian troops have surrounded the hotel. The roads leading to the hotel have been sealed off.
Mali has urged its residents to stay where they are and not venture out during the hotel siege.
Turkish Airlines said six of its personnel are trapped in the hotel. French, Nigerian and Chinese nationals are also among those being held hostage.
Authorities said the gunmen rode up to the hotel in a vehicle with diplomatic license plates.
'Shelter in place'
The U.S. embassy in Mali said in a statement Friday: "The Embassy is aware of an ongoing active shooter operation at the Radisson Hotel." The embassy urged all U.S. citizens and the embassy staff to "shelter in place."
A security source said the gunmen are on the seventh floor on the Radisson Blu Hotel in Bamako. "Jihadists are firing in the corridor," the source told AFP.
U.S. President Barack Obama, who is attending the Association of Southeast Asian Nations (ASEAN) meeting in Malaysia, has been briefed on the hostage situation in Mali and has asked his staff to keep him up-to-date on developments.
The attack in Mali underscores the threat posed by Islamist militants who remain active in northern and central Mali despite the presence of U.N. peacekeepers.
A French-led military force ousted Islamist groups from power in northern Mali in 2013. The groups had seized power in the north after a military coup in Bamako in 2012.
An attack in the capital in March at a restaurant popular with tourists killed five people.