WASHINGTON — The U.S. and Russia have expelled five diplomats and military attaches from each other's countries in moves reminiscent of the tit-for-tat exchanges of the Cold War-era, U.S. officials said Thursday.

The latest expulsions, ordered by Russia on April 28, were of two American military attaches at the U.S. Embassy in Moscow. They were preceded by the expulsion of a Russian diplomat from Washington on April 22, the expulsion of a U.S. diplomat from Moscow on April 14 and the expulsion of a New York-based Russian diplomat on Nov. 6, 2007.

The State Department said Thursday that Russia's most recent action was "not justified" but that it would comply with the order. It also sought to tamp down speculation that the series of expulsions could escalate. Spokesman Sean McCormack said the U.S. was treating them as separate incidents and that Washington considered the matter closed.

"We're not making any particular connection between the expulsion of these two individuals and any previous steps that we might have taken," McCormack told reporters. "As far as we're concerned, we don't intend to take any further actions. We always reserve the right, but at this point I don't see that we're going to take any further action in response."

On Capitol Hill, the top U.S. diplomat for Europe, Daniel Fried, told a congressional hearing that he did not believe the expulsions signaled any deterioration in relations with Russia.

"We look at these incidents as something which happens from time to time in U.S-Russian relations," he said. "It is not in our view the sign of some larger diplomatic struggle. It is not a sign of some downturn."

Neither McCormack nor Fried would discuss the reasons for the expulsions but, speaking earlier, U.S. officials said that none of those involved had been declared "persona non grata" by either government and that none had been accused of specific wrongful conduct, such as espionage.

In Moscow, the Russian Foreign Ministry declined to comment.

During the Cold War, the U.S. and the former Soviet Union routinely expelled diplomats from the other country, often over spying allegations.

Although U.S. officials played down any linkage among the cases revealed Thursday, news of the expulsions came at a time of uncertainty in U.S.-Russian relations with the arrival in power of new Russian President Dmitry Medvedev and his former boss, Vladimir Putin, who became prime minister Thursday.