March 22, 2001 -- In a return to the days of Cold War games, a diplomatic face-off was launched today between Washington and Moscow with the expulsion of dozens of Russian diplomats suspected of spying America.

Four Russian diplomats have been declared “persona non grata” and ordered out of the country in 10 days as a result of the Robert Hanssen spy case and another 46 have been asked to leave by July 1, a senior State Department official said today.

Two other Russian diplomats believed to be directly related to the Hanssen case had already left the country, the official said.

Hanssen, a 25-year FBI veteran, was arrested in a Virginia park on Feb. 18 after allegedly trying to make a “dead drop” to his Russian handlers. He is accused of spying for the Soviet Union and Russia since 1985.

Today's announcement of the expulsions came a day after Secretary of State Colin Powell called Russian ambassador Yury V. Ushakov to advise him of the action Washington was planning.

While the six Russian diplomats are believed to have direct links with the Hanssen case, the State Department official said the 46 diplomats were expelled partly out of long-standing concerns with the heightened level of Russian intelligence operations in the U.S., which had increased significantly between 1993 and 1997.

'A Political Act'

With the formal announcement made, all eyes were turned to Russia as U.S. officials were expecting Moscow to retaliate to the expulsion order.

In the first direct official response to the order, Russia's Foreign Minister Igor Ivanov called the expulsions a "political act" and said the U.S. had flimsy grounds for the order.

In a statement read over state-controlled ORT television today, Ivanov expressed regret that Washington had resorted to the expulsion order. "If anyone had any questions or doubts, this could easily have been settled along ... special channels and by special contacts," he said. "Unfortunately, Washington has chosen another way, so this step cannot be regarded as anything but a political one," Ivanov said.

Earlier, Russia’s Itar-Tass news agency quoted an unnamed high-ranking law-enforcement official as saying the “response may affect representatives of all divisions of the U.S. intelligence community working under diplomatic cover.”

He also noted that the Russian embassy in Washington employs 190 people, while the U.S. embassy in Moscow has 1,100, perhaps hinting that the number of Americans asked to leave the country would be larger than the number of Russians expelled from the United States.

Bush 'Extensively Involved' in Decision

On its part, the Bush Administration has been attempting to play down fears that the expulsion order would lead to a deterioration of relations between the U.S and Russia.

Speaking to reporters in Washington today, White House spokesman Ari Fleischer said, "The president looks forward to having a productive relationship with Russia." He added that Bush was looking to have a policy that was "marked by realism."

Earlier today, National Security Adviser Condoleeza Rice said the large Russian diplomatic presence in the U.S. was "just not representative of the kind of relations we would want to have with Russia."

Latest in a Tit-for-Tat Spook Hunt

Washington and Moscow have exchanged tit-for-tat spy allegations since the end of the Cold War, with each side often responding quickly to such charges with ones of their own.

But the expulsion of 50 diplomats will be the largest by the United States since the Reagan administration ordered 55 Soviets to leave in 1986, done partly in retaliation for the then-Soviet Union’s previous expulsion of five U.S. diplomats.

While the action comes partly in retaliation for the discovery of Hanssen’s alleged activities, sources noted the expulsions were prompted by a potential espionage trend that concerned the Bush administration.

Intelligence gathered by the United States indicates there are now more Russian spies infiltrating the country than at any time since the Cold War, officials said.

Senior Bush administration officials said the decision to expel such a large number of Russian diplomats was based on reliable evidence.

Hanssen is alleged to have done #0147;exceptionally grave,” damage to U.S. intelligence amd compromised the identities of U.S. agents.

Officials also suspect he may have alerted Moscow to a secret tunnel underneath Russia’s U.S. embassy in Washington D.C., which the FBI reportedly used for eavesdropping.

Hanssen is being held without bail.

ABCNEWS' Pierre Thomas in Washington and Sergiusz Morenc in Moscow contributed to this report.