A group claiming to be the Kosovo Liberation Army, the disbanded guerrilla force that fought for independence against Serb forces during the 1998-1999 conflict, distributed an email statement saying it had carried out the bombing.
The statement said the KLA had regrouped in order to "avenge the death of two protesters" during a recent demonstration in Pristina.
Police have not commented on the statement, the authenticity of which could not be independently verified.
The two protesters were killed 19 days ago during clashes between police and supporters of "Self-determination" - an ethnic Albanian pro-independence movement.
Though still a Serbian province, Kosovo has been run by the UN since mid-1999, after a Nato bombing campaign helped end a crackdown by Belgrade-controlled forces against ethnic Albanians.
Martti Ahtisaari, the UN special envoy for Kosovo, is due to hold talks with Serbian and Kosovo authorities in Vienna on Wednesday over plans for the future status of the Serbian province.
Belgrade has rejected Ahtisaari's plan, which calls for self-governance for Kosovo under international supervision.
Agim Ceku, Kosovo's prime minister, condemned the bombing as "an act of those opposing the process of Kosovo's independence".