"Kosovo has its borderlines and any attempt to divide it ethnic-wise is an extremist proposal for the solution of its status which will not be accepted either by the Kosovo side or any other democratic country," Kosumi said in Pristina on Friday.
Tadic has recently suggested that this UN-administered province be divided into an Albanian-populated entity and the other one belonging to the Serbs.
Kosumi assessed that such a proposal was contrary to guidelines which the international community defined for the ongoing negotiations on the status of this area which is formally the Serbian southern province.
Kosumi added that Kosovo entered the negotiations with an aim to become an independent country.
The UN Special Envoy for Kosovo, former Finnish President Martti Ahtisaari, on Thursday arrived in Belgrade for talks with Serbian officials. On Friday he is expected to meet Tadic.
Ahtisdaary already was in Pristina, and is to visit other capitals in the region as part of his shuttle diplomacy.