by Sebastian Alison and Lyubov Pronina, Bloomberg News Service

MOSCOW - Russian President Dmitry Medve-dev wasted little time in laying down his first challenge to Barack Obama.

Hours after Obama won the U.S. presidential election, Medvedev said Wednesday he'd put short-range Iskander missiles in Kaliningrad, a region wedged between Poland and Lithuania, to "neutralize" a planned U.S. missile-defence system. A radio- jamming installation there will also be aimed at elements of the U.S. system in Poland and the Czech Republic, he said.

The plan highlights the hurdles Obama faces in improving frayed ties with an increasingly assertive Russia. While Obama's criticism of the war in Georgia and his support of NATO's eastward expansion are similar to those of defeated Republican rival John McCain and President George W. Bush, he has indicated flexibility on the missile shield.

"There's no question that this is designed as a test for the Obama administration," said Kimberly Marten, a professor of political science who specializes in Russian foreign policy at Columbia University's Barnard College in New York.

Medvedev's words don't add up to much strategically and aren't likely to affect how Obama views the U.S. missile system, she said by telephone.

'POSTURING'

"It's posturing," she said. "Kaliningrad is already so heavily militarized -- there are tactical nuclear weapons from the Russian side there -- so these missiles wouldn't actually have any particular major impact on the defence balance in the region."

Krzysztof Bobinski, director of the Warsaw-based Unia & Polska Foundation, a political institute, said Medvedev's words are the "first test for Obama."

"The Russians think that the new U.S. president isn't sure about the missile-defence plan, and want to try to shake his resolve," he said by phone.

U.S. allies bordering Russia reiterated the U.S. position that the missile shield isn't directed at Russia and doesn't represent a threat to their former Soviet masters.

Polish Prime Minister Donald Tusk told reporters in Warsaw that Medvedev's remarks should be treated as "a political, not a military, declaration" and shouldn't be taken "too seriously." Lithuanian President Valdas Adamkus issued a statement calling the plan "beyond comprehension."

"This is a warning to Obama -- a bright, clear warning -- that tough negotiations are ahead," Alexander Rahr, a Russia expert at the German Council on Foreign Relations in Berlin, said by telephone. Medvedev's "fist-waving" on the missile shield may be premature, since Obama has shown less support for the system than President George W. Bush, Rahr said.

Obama said he'll back the plan "if it works and if it can be financially feasible," said Michael McFaul, a Russia specialist at Stanford University who advised him during the campaign, in an interview last month. Obama's campaign didn't return telephone messages seeking comment.

Some Russian officials said Medvedev ought not push Obama into a major foreign-policy test.