Bulgaria's outgoing government greenlighted on Thursday a last-minute deal with Toshiba's US nuclear engineering unit Westinghouse to build a new reactor at the country's Kozloduy nuclear power plant.

Energy is an extremely sensitive issue in the European Union's poorest country, which is seeking to wean itself away from almost total dependence on Russia for its gas and nuclear fuel imports amid flaring tensions over Ukraine.

The Socialists-backed government, which resigned last Wednesday, has come under strong media pressure not to sign any last-minute agreements.

"The government adopted a decision approving the report of the minister of economy and energy on signing a shareholder agreement between (the state-owned) Kozloduy NPP and Westinghouse Electric," it said in a statement.

But the deal will also need approval by any new government voted in by snap elections on October 5 before it enters into force, the statement added.

Westinghouse chief executive Danny Roderick paid a one-day visit to Sofia on Tuesday, when he pressed for a shareholder agreement on building the 1,100-megawatt AP-1000 reactor to be signed "as soon as possible."

This would allow the 5.0-billion-dollar (3.7-billion-euro) project to get going despite lingering political uncertainty, Roderick told the Trud daily newspaper in an interview.

Westinghouse planned to take a 30-percent stake in the project, and the US Import-Export Bank was also ready to offer a package for funding it, he added.

Bulgaria hopes that the new unit at its Soviet-built power plant on the Danube will help it diversify its energy sources at a time when the West is ratcheting up sanctions against Moscow over the crisis in Ukraine.

Safety concerns had forced the closure of four of Kozloduy's total of six units on the eve of Bulgaria's European Union accession in 2007, leaving just two 1,000-megawatt reactors in operation at the plant.