A grenade attack on a nightclub in the centre of the Kenyan capital, Nairobi, has injured 13 people.
The grenade was thrown into the Mwauras club early on Monday morning.Police have not said who was behind the attack, but correspondents say some will blame Somali militants al-Shabab.
It comes a week after Kenya sent troops to Somalia to track down members of the group, which Nairobi blames for several kidnappings. Al-Shabab threatened reprisals if the troops did not leave.
The al-Qaeda-linked Islamist group, which controls much of southern and central Somalia, has denied carrying out any abductions.
'Imminent threat' "Initial investigations show it is a grenade that was thrown inside," said Eric Mugambi, a senior police officer in Nairobi.
A local news station, Capital News Radio, quoted a witness as saying a man had asked to be let in to the Mwauras bar in central Nairobi shortly after 03:00 (0000 GMT). He then hurled a grenade and fled the scene, said the witness.
Lawrence Kioko, who was injured in the attack, told Reuters news agency: "I heard an explosion - there was darkness and I thought the electricity had gone out but when I touched my face, there was blood."
Witnesses said a man threw a grenade into the club and fled the scene. "The guys came out running covered in blood. We helped them wash the blood off and they were carried away in ambulances," Jacob Musembi, an eyewitness, told Reuters.
Police cordoned off the area. No group has so far admitted carrying out the attack.
Deputy police spokesman Charles Owino said no-one could be ruled out.
"We know that there are al-Shabab sympathisers in Nairobi," he said. "But it could also have been a business dispute. It is too early to say."
Last week, Kenya announced it would carry out a major security operation in Nairobi to flush out al-Shabab sympathisers once its Somalia operation had ended.
The US embassy in Nairobi warned on Saturday of an "imminent threat" of attacks in Kenya.