There's been more gunfire in Nairobi as Kenyan special forces remain in a stand-off with militants in a shopping mall.

The Somali militant group al-Shabaab says it's behind the attack at the Westgate centre, which has killed at least 39 people.

An unknown number of hostages are being held on the second floor.

Kenyan officials say an unknown number of hostages are still being held after a suspected terrorist attack in a shopping mall.

Kenya's president has urged people in Nairobi to remain calm.

Radio presenter Sadia Ahmed witnessed the shooting.