Romania's recent decision to allow U.S. missile interceptors on its territory was welcomed by Washington, but understandably raised suspicion in Moscow.

Russia was concerned about the U.S. missle shield plan and asked for an explanation from the U.S. side, said the Russian Foreign Ministry in a statement issued Friday.

Analysts say the Romanian decision came at a crucial moment when Washington and Moscow are about to sign a successor document to the expired Strategic Arms Reduction Treaty (START-1). Therefore, the move may upset the thawing Russia-U.S. relations and put their bilateral ties to test.

Romania: for its own security

Analysts say Romania joined the U.S. missile defense system out of national security concerns and a desire to gain an important position in the U.S.-led global security system.

Since the drastic political shakeup in 1989, Romania has made seeking Western military protection a high priority for its foreign policy. It has tried by all means to form closer ties with the United States and joined the North Atlantic Treaty Organization (NATO) in 2004.

Last Thursday, upon getting a request from visiting U.S. Under Secretary of State Ellen Tauscher for Romania to join the missle defense system, Basescu called a meeting of the country's top defense body and decided to give Washington a positive response.

As Romanian ruling parties and the opposition share similar views on national security policy and favored a closer stategic partnership with the United States, it is widelly believed that the government's decision will be approved by the parliament.

President Basescu stressed that "Romania will not host a system directed against Russia, but against other threats." But analysts believe such a move would only make the already strained relations between Romania and Russia even worse.

Russia: concerned but with restraint

Russia responded strongly to Romania's decision, and expressed grave concerns over the move.

Russian Representative at NATO Dmitry Rogozin said Friday that the United States had pushed its missile defense system closer to Russian borders, and it could direct the system at any country including Russia's nuclear capability.

As the United States and Romania only cut a deal in principle without starting negotiations on details, Moscow has so far showed restraint, wishing to solve the issue through dialogues.

Some Russian experts and legislators suggest Russia link the missile defense issue with the ongoing talks on the successor document to the START-1, but Russian Foreign Minister Sergei Lavrov and his ministry sounded very cautious in their statements, without mentioning the proposed linkage.

Moscow seemed reluctant to let Romania's move disrupt negotiations on new nuclear arms reduction agreement. Russian Vice Premier Sergey Ivanov also told the annual Munich security conference Saturday that the new treaty is expected to be signed and approved this year.

Analysts say if Russia considers the U.S. missile defense system a serious threat to its national security, there is the possibility for it to deploy short or medium range missiles in its neighboring regions.

U.S.: continue to reassure Russia

The U.S. government has not given an official response to Romania's decision to join the missile defense system, nor have the U.S. mainstream media made any comments on the issue.

Analysts noted that the Obama administration abandoned his predessor George W. Bush's version of the missile defense plan, but that does not mean Obama had also given up the plan's goals of guarding against Iran and containing Russia.

Despite a lack of mutual trust, the United States and Russiait are moving toward a "new detente" after their relations hit a record low during the Bush administration. As leaders of the two countries have reached a consensus on mending their bilateral ties, more dialgues and less confrontation have become the main trend of the U.S.-Russia relations.

Analysts noted that as nuclear arms reduction bears on the common interrest of Russia and the United States, neither country will use it as a bargning chip to further its own interest. Therefore, it seems unlikely the deployment of missile defense system will stall the ongoing nuclear arms control process.