MOSCOW, DEC. 11 -- KGB chairman Vladimir Kryuchkov said tonight that the secret services would wage battle "with all the means at their disposal" against "anti-communist" forces from within the country and abroad that threaten the authority of Soviet central power.

"To be or not to be, that is the choice for our great state," Kryuchkov said in a televised statement.

"The KGB has made its choice, to defend the socialist motherland. . . . The KGB will protect law and order and block all forces trying to tear the union apart."

Kryuchkov's hard-line statement clearly is a part of Soviet President Mikhail Gorbachev's attempt in recent weeks to reassert the Kremlin's authority against nationalists in the Baltic states and other republics who reject his idea of a "renewed" union and challenge Moscow's traditional control over the economic and political system.

To some extent, Gorbachev's speeches and Kryuchkov's statement are a form of political theater, an attempt to reassure the country at a moment when its primary concerns are the collapse of the food distribution system and increasing social problems such as a rapidly rising crime rate.

Kryuchkov said black-marketeers and economic "saboteurs" are not only trying to profit from the current food crisis, but also are "bidding to liquidate Soviet power."

Kryuchkov went beyond the law-and-order message in Gorbachev's recent statements and implicit in his appointment last week of Boris Pugo, the former Latvian KGB commander, as the new Interior Ministry chief.

Kryuchkov also directed his salvo at Western intelligence agencies whom he said are exploiting the current instability in the Soviet Union.

"Certain radical political movements are being masterminded by foreign support," he said. "When our country needs unity as never before, we are coming up against forces who would undermine our fraternity."

Kryuchkov, who previously was the head of the KGB's foreign intelligence directorate, warned that "no foreign intelligence agency should interfere" in Soviet domestic affairs. "For decades," he continued, "they have been waging an undeclared war and continue to do so."

Both KGB and CIA officials have said that, despite the closer relations between the Soviet Union and the United States since Gorbachev came to power in March 1985, spying on both sides has increased.

Kryuchkov said the country could no longer tolerate the "battle of laws," in which the republics' parliaments contradict laws passed in the Supreme Soviet or ignore Gorbachev's presidential edicts.

As if to take the ominous tone off his statement, Kryuchkov was quick to remind viewers that he was "authorized" to act by the government and that the KGB supports reforms in the country.

Nevertheless, some of Kryuchkov's language was startling: "The danger of the Soviet Union's disintegration has developed. National chauvinism is being fanned up, and mass rioting and violence are being provoked."

He said the KGB had discovered that certain groups -- whose names and locations he did not identify -- had written "blacklists" of "people who must be neutralized, if need be." The KGB supports democratic change, Kryuchkov said, "but without law and order, democratization and openness are merely high-flown words."

The KGB has appeared to feel threatened in recent months, not only by heavy public criticism within the country but also by the specter of attacks on security forces in Eastern Europe after the democratic revolutions there in 1989.

In Georgia, dissident political leader Zviad Gamsakhurdia led a full-scale attack on KGB headquarters in Tbilisi in September, and two months later was elected president of the republic.

In Lithuania, the defiant parliament in Vilnius has set up an alternative secret service, led by lawmaker Mecys Laurinkus, and has demanded that the Soviet KGB leave its territory.

Representatives in Estonia, Latvia and Lithuania all have said they expect a crackdown in the near future. A few months ago, Moscow seemed prepared to negotiate with the Balts on independence, but now Gorbachev is demanding once more that republics that do not sign the proposed union treaty go through a secession process that would involve a popular referendum and a "negotiations period" of five to seven years.

The Communist Party Central Committee today approved Gorbachev's draft of the new union treaty that he says is needed to hold the 15 Soviet republics together.

But the parliament of the Russian Federation and the president of Kazakhstan, the third-largest Soviet republic, said they would sign the proposed treaty only if it gives them control over their own economies, the Associated Press reported.

Kryuchkov's statement came just hours after the Central Committee closed a two-day plenary session, during which, sources said, many members made speeches expressing outrage at the Kremlin's seeming inability to cope with the "battle of laws."

Non-communist parties are in the majority in the legislatures of six republics: the three Baltic states, Armenia, Moldavia and Georgia.

The leader of the huge Russian republic, Boris Yeltsin, quit the Communist Party last July.