MOSCOW, FEB. 13 -- Gennadi Filshin, deputy premier of the Soviet Union's giant Russian republic, resigned today in what he described as a protest against KGB attempts to discredit him and Russian President Boris Yeltsin.

Filshin, a strong supporter of radical economic reform, said the KGB secret police and Communist Party hard-liners were conducting a "witch hunt" to end the influence of reformists in the legislature of the Russian republic and to block attempts by that body to implement economic change. Reformists hold a slim majority in the Russian legislature and are perhaps the most important organized opposition to the resurgent hard-line stance taken by the Soviet central leadership.

Last week, Yeltsin's aides charged that the KGB was tapping the Russian leader's phones and said they found the room above Yeltsin's office filled with eavesdropping devices.

Filshin's resignation appears to be part of a Byzantine political struggle between the leadership of the Russian republic and the Kremlin. It may be related to a business deal that Filshin, who was deputy premier for economic affairs, closed between Russia and a Western firm. Earlier this week, Soviet Prime Minister Valentin Pavlov charged that Western and Soviet banks had been seeking to overthrow President Mikhail Gorbachev by destroying the country's financial system, and he indicated that the Russian deal was part of this scheme.

According to accounts in the independent business magazine Commersant, Russia and the British firm Dove Trading International completed a 140-billion-ruble deal earlier this month under which the two parties agreed that Dove and other Western suppliers would be allowed to sell foreign consumer goods -- for rubles -- in the Russian republic. The foreign firms would then invest the proceeds in the development of local property and industries with the aid of the Russian government.

The arrangement was designed to circumvent investment and return problems posed by the nearly worthless, inconvertible Soviet currency and to try to provide Russian citizens with much needed quality goods. But, Commersant reported, the deal was short-circuited after KGB agents searched Dove president Colin Gibbons at the Moscow airport, confiscated all documents relating to the trade agreement, took his fingerprints and interrogated him. The Soviet state bank has since declared the Dove-Russia deal illegal.

Filshin said Kremlin authorities opposed the deal with Dove because it bypassed the central government planning apparatus, an assessment seconded by other Russian officials who long have complained that the Kremlin has undercut their efforts at radical reform in order to retain control of the country's economy within the Soviet bureaucracy.

In his letter of resignation, Filshin said he was determined to protest "what is obviously an anti-democratic campaign of provocation. . . . With this act, I want to attract attention to the alarming events taking place all over the country."

Filshin's remarks were reminiscent of Eduard Shevardnadze's dramatic resignation as foreign minister in December, in which he warned publicly of a "coming dictatorship." One of Filshin's closest colleagues in the Russian legislature, Grigori Yavlinski, quit that body in November after Gorbachev sided against the advocates of radical economic reform and refused to go forward with the so-called "500 Day Plan" for a swift transfer to a free-market system.