VILNIUS, April 22 (Reuters) - Lithuania revived doubts on Tuesday about lifting its block on European Union talks with Russia, a day after the Baltic country's foreign minister said Vilnius was not vetoing the talks.

 "Lithuania has no intention of blocking the talks in principle and would like to see EU-Russia cooperation advanced, however this cannot happen at the expense of Lithuania's interests," said Violeta Gaizauskaite, a foreign ministry spokeswoman on Tuesday.

"Lithuania has not decided yet whether or not to approve the mandate for EU-Russia talks," she added.

On Monday her boss had declared:

"We are not vetoing the (EU-Russia) talks... We are not talking about any blockade," Lithuanian Foreign Minister Petras Vaitiekunas told Reuters after a meeting with President Valdas Adamkus.

A day later Lithuanian diplomats said the Baltic state wanted the EU to include into the talks mandate, four declarations; covering energy security, the solution of conflicts in Georgia and Moldova, Russia's cooperation in some criminal cases and compensation for resettlement expenses incurred when former inmates of Soviet gulags returned to Lithuania.

Diplomatic sources in the EU presidency said Lithuania had not lifted its opposition to the start of talks, but they hoped for a compromise this Thursday at an EU ambassadors' meeting.

The EU diplomats said they were working to resolve Lithuania's concerns, but some warned a stalemate was possible.

A high-ranking Lithuanian diplomat told Reuters Vilnius saw no need to rush approving the mandate next week, as the start of the talks was expected in a couple of months.

"We still have time for negotiations," he said.

EU foreign ministers next Monday are expected to discuss the mandate covering talks with Russia on trade, economic development, energy, human rights and political cooperation.

The actual talks themselves could be launched at an EU-Russia summit in Siberia on June 26-27 -- the first with President-elect Dmitry Medvedev, diplomats have said.

Vaitiekunas also said on Monday that Lithuania was concerned about the lack of a response from Moscow to its requests to explain the fate of crude-oil supplies after Russia cut its oil pipeline in 2006. He said Lithuania was concerned a similar cut could be made to supplies of gas from Russia.

Lithuania has also complained about the lack of Moscow's cooperation in investigating the disappearance of a Lithuanian businessman in the neighbouring Russian enclave of Kaliningrad.

Poland recently lifted its long-standing veto to the talks after Russia ended its embargo on imports of Polish meat and other food products.

Poland, Lithuania and some other EU newcomers from central and eastern Europe believe Russia is using its position as a major supplier of energy to the bloc to advance its increasingly assertive foreign policy agenda.