Two people have been killed and 11 injured in an explosion in Pristina, the capital of Kosovo, police say.
The blast struck a shopping and business area early on Monday morning. Police said they did not know the type of explosives or who was responsible.
Police and troops from Nato-led peacekeepers have sealed off the area.
Kosovo – currently part of Serbia – has been governed by the UN since 1999. Talks are due this week in New York on its final status.
Police spokesman Veton Elshani told Agence France-Presse news agency: "The blast occurred at 0210 (0010 GMT) in the business area in which some coffee shops and restaurants were still working."
One person died at the scene and another in hospital, he said.
Tension has been rising as the 90% ethnic Albanian population pursues its bid for independence from Serbia.
The ethnic Albanian leadership and a senior Serbian team will meet on the sidelines of the UN General Assembly in New York.
Western nations have supported the independence plan but Serbian ally Russia has blocked it in the UN Security Council.
Serbia prefers a broad autonomy package.
The US has set a deadline of 10 December for a final decision on Kosovo’s fate but Russia rejects this.