Serbia's pro-Western and nationalist leaders are split over whether the country's caretaker government can ratify a key energy deal with Russia.
The deal envisages that part of a pan-European gas pipeline run through Serbia, and that Russia buys a majority stake in Serbia's state oil monopoly.
Nationalist Prime Minister Vojislav Kostunica says Russia has asked for the deal to be ratified in the Serbian parliament as soon as possible. It was signed in January.
But pro-Western officials said the government and parliament don't have legal capacity to ratify strategic deals.
President Boris Tadic said the energy deal should wait for a new government that will be established after May 11 elections.