Bulgaria's Prime Minister Boiko Borisov said last week the country would not go ahead with either project, citing a lack of investment for the nuclear power plant and environmental concerns for the pipeline. Bulgaria's energy minister then said that Sofia had yet to make the final decision on the two energy projects.

Later, Borisov said his quotes were not carefully worded and an assessment on the environmental impact of the Burgas-Alexandroupolis pipeline would decide whether the project goes ahead.

Russia respects Bulgaria's positions on the Belene nuclear power station and the Burgas-Alexandroupolis pipeline, Bulgarian daily 24 Chasa quoted the Russian ambassador to the Balkan state, Yuri Isakov, as saying.

"We favor and have 100% understanding of the Bulgarian party's position," Isakov said.

"The issue is very sensitive and it would have been really unreasonable to start this project without 100% certainty it is absolutely safe for the environment," the Russian diplomat said.

Although there are no reasons to doubt Sofia's reasons for suspending the joint projects with Russia, Borisov's comments came shortly after the Bulgarian government confirmed that the country was considering the possible deployment of elements of the U.S. missile defense system on its territory.

Analysts say that Borisov, whose course is strongly targeted at integrating Bulgaria into European structures, is likely to be less inclined than his predecessors to maintain traditionally close ties with Russia.

Russian officials say Moscow could find other partners to do business with.

"Recently Bulgaria was offered to participate in the Blue Stream gas project," Isakov said. "For a year or two, Bulgaria has been giving vague answers to the proposals and has shown no interest in the implementation of the project. In the end, this project was carried out in cooperation with our Turkish partners."

"Who won and who lost from this?" he asked. "The question is to be addressed to you [Bulgaria]. All in all, we live in a very competitive world. We say in Russia, a sacred place is never left empty. We will always find partners to implement our energy projects. And trust me, there are many willing partners."