Russia briefly detained an American diplomat yesterday, accusing her of spying and saying she was "caught red-handed." The Russian foreign minister said the American would be leaving Moscow soon.

The temporary arrest of Cheri Leberknight, 33, a second secretary in the U.S. Embassy, came a day after the disclosure that a U.S. Navy petty officer was charged with espionage in the United States for passing information to Russia. However, both Russian and U.S. officials said there was no link between the cases, and American officials in Washington attributed Leberknight's detention to an ongoing tug of war between U.S. and Russian intelligence agencies.

In Moscow, Alexander Zdanovich, spokesman for the Federal Security Service, said Leberknight was "caught red-handed trying to get from a Russian citizen documents on military and strategic information classified as state secrets."

The embassy spokesman had no comment. Leberknight was later released and Foreign Minister Igor Ivanov said she "will leave Moscow shortly," according to the Interfax news agency. Ivanov said there is "exhaustive evidence implicating her in activities incompatible with her official status."

Zdanovich said Leberknight was in possession of "certain spy paraphernalia," which he said included "a detailed map of the place where a meeting was supposed to take place," and "special equipment designed to detect communication between surveillance agents."

He said she was detained in Moscow's Izmailovo district while waiting for a Russian citizen.

Zdanovich denied the case was a reaction to the charges in the United States against Daniel King, 40, for passing secrets to the Russian Embassy there in 1994. King had been assigned to a decoding unit at the National Security Agency in Fort Meade, Md., at the time of the alleged espionage. He was arrested Oct. 28 and charged Nov. 5.

"We do not want to link these two cases if only for the sole reason that the eye-for-an-eye principle is alien to us," he said. "It's a Cold War principle."

In Washington, intelligence officials attributed the detention and expected departure of Leberknight to tensions between American and Russian intelligence agencies.

They also said it was not related to the arrest of King. According to a senior Pentagon official, King has admitted mailing a computer disk of data to the Russian Embassy in 1994. It included information on the use of U.S. submarines to eavesdrop on Russian undersea communications cables, the official said.

The tension between American and Russian intelligence services results, in part, from the Clinton administration's unsuccessful attempts to persuade Moscow to cut back espionage operations against the United States. Administration officials say Russia reduced the number of spies in America after the breakup of the Soviet Union in 1991. But they say that in recent years Moscow has stepped up its espionage activity to near-Cold War levels.

One U.S. intelligence official said the expulsion of Leberknight may also be connected to Russian politics, noting that Prime Minister Vladimir Putin formerly served as director of the Federal Security Service, Russia's internal security force. "Anything anti-American is popular to their electorate," the official said.

The case against King developed this year when a polygraph test during a routine screening for continued access to classified information indicated deception by the 18-year Navy veteran. Pentagon sources refused to say exactly when the classified information allegedly was delivered, although one source said it was a single episode.

King is awaiting trial in the brig at the U.S. Marine base in Quantico, Va. If convicted, he could face the death penalty for espionage.

Hoffman reported from Moscow.

CAPTION: Russian television shows a photo of woman identified by Russian Tass news agency as Cheri Leberknight.