Russia has become more rigid in dealing with the United States on issues such as Washington''s plans for a missile shield in Europe and looks set to test the new administration of President-elect Barack Obama, a senior U.S. diplomat said on Wednesday.

Under-Secretary of State for Arms Control and International Security John Rood said talks in Moscow this week that failed to narrow differences the missile shield plan suggested Russia was pausing to take stock of the Obama team.

"They have paused with the election of a new administration in the United States and they are looking carefully at the position of the new team," he told reporters.

"My assessment is that the Russians intend to test the mettle of the new administration and the new president," said Rood.

He said Russia''s stance on the missile shield and other issues was "less flexible" than it had been in previous talks.

Russia rejects U.S. reasoning that interceptor missiles in Poland and a radar in the Czech Republic are needed to avert potential missile strikes from Iran.

Moscow says the project is targeted against it and has threatened to place missiles in its western enclave of Kaliningrad, near Poland.

Obama, who is to be sworn in as president on January 20, has said he would make sure any missile defense system has been proven to work before it is deployed.