"It is very important to us that Poland joins the project," Kirkilas said in an interview broadcast on privately owned Zinius radio, without going into detail about what role he envisaged for Poland in the construction of a new facility to replace Lithuania's ageing Ignalina nuclear power station.

"We will be able to comment on that question Friday after a meeting of prime ministers of the Baltic states" in Vilnius, where energy will be high on the agenda, Kirkilas said.

The leaders of the three Baltic states, which depend heavily on outside sources for their energy needs, backed in February the construction of a new nuclear facility to replace Ignalina, which uses reactors like the one that exploded at Chernobyl in 1986, provoking the world's worst nuclear disaster.

In July, Kirkilas invited Poland to be part of the project to replace Ignalina, but last month Polish President Lech Kaczynski refused to commit his country.

Officials in Latvia and Estonia voiced opposition to Poland coming on board, indicating that Friday's meeting in Vilnius could be turbulent.

"We are happy with the cooperation of the project partners so far," Estonian Prime Minister Andrus Ansip said.

"The involvement of new partners could take place if a consensus is reached by all parties," he added.

Under the agreement signed by the Baltic prime ministers in February, the nuclear project would be managed equally by the energy companies of Estonia, Latvia and Lithuania. Bringing in an additional partner requires consensual agreement among the three, according to the document.

The aim of the new facility is to meet "the power needs of all three countries", the agreement says.

Involving Poland "might cause a situation in which the production capacities of the new power station would be insufficient," warned Ansip.

Latvian Foreign Minister Artis Pabriks hinted that the three countries were capable of carrying out the project themselves, and stressed it was vital to ending the region's energy isolation.

"The Baltic countries have historically been isolated in energy terms. We support any project that could unify the Baltics with the EU," Pabriks told reporters in Riga.

"Our national energy companies have done the calculations to assess the costs of the project. We are capable of doing this ourselves," he said.

A feasibility study conducted by energy companies from the three Baltic states, which was approved by two Lithuanian parliamentary panels on Wednesday, said building the new nuclear plant would cost between 2.5 - 4.0 billion euros (3.15 - 5.0 billion dollars).

The study determined that the new facility would not come onstream before 2015, leaving a six-year gap between the closure of Ignalina in 2009 and the inauguration of the new plant.

During that time, the Baltic states, and especially Lithuania, which derives 80 percent of its electricity needs from the existing nuclear plant, will have to seek energy sources elsewhere.

The Baltic states, which were Soviet Republics from the end of World War II until 1991, are all still heavily reliant on Russia for supplies of natural gas and oil, and their power grids remain linked to that of their former ruler, despite having joined the European Union in 2004.

Poland, also a new EU member, and Lithuania will sign a deal Friday to link their power grids, while Estonia inaugurated this week an undersea cable linking its grid to that of Finland.

Both deals are seen as steps towards loosening Moscow's energy grip on the Baltic states.

str-burs/kdz/wai