MOSCOW, JULY 3 -- The KGB has little left to hide because most of its secrets have been taken abroad by a score of defectors since 1980, a former top-level KGB official said in an article published here today.

Former KGB Maj. Gen. Oleg Kalugin -- who was stripped of his rank and decorations last week for making other public revelations about the secret intelligence and police agency -- said also that in the seven years he headed counter-espionage operations abroad the KGB had failed to infiltrate the CIA with even one undercover operative.

"From 1960 to 1980, three KGB officers defected to the West," Kalugin wrote in Komsomolskaya Pravda, the Communist youth newspaper. "And since 1980, about 20 people betrayed the country; the latest defector went to Belgium this spring. So we can speak not about a leak of information, but about the transfer and sale to the West of the majority of secrets of Soviet intelligence, about the complete collapse of a huge number of spy networks."

Kalugin, who says he was forced to retire in March after a falling out with his superiors, accused the KGB last month of trying to discredit populist Communist politician Boris Yeltsin and Premier Nikolai Ryzhkov, and -- despite the security agency's claims to the contrary -- of maintaining a strong clandestine presence in every Soviet institution and organization.

The KGB -- the Russian initials for Committee for State Security -- responded with a sharp attack in the Communist newspaper Pravda saying Kalugin had embarked on the road to treachery and that weakness of character lay behind his disclosures.

The Pravda article portrayed Kalugin as an ineffective official whose blunders had caused Soviet intelligence to lose one of its most prized agents inside the CIA. But Kalugin, in his article today, said there had been no such agent. He was stripped of his rank and medals Saturday in orders signed by President Mikhail Gorbachev.

Komsomolskaya Pravda also published a letter today from several Soviet legislators urging an investigation of Kalugin's disclosures about the KGB. The letter urged that the legislature, or Supreme Soviet, examine the KGB's budget, operations and methods and find out how it is controlled and to what extent it still penetrates public organizations.

Meanwhile, KGB chief Vladimir Kryuchkov defended his agency's work in a speech to the 28th Soviet Communist Party Congress here today, telling the delegates that it is unmasking foreign agents by the dozens and is still needed to help round up domestic "instigators and extremists."

Kryuchkov, a member of the Communist Party's ruling Politburo, warned that the Soviet Union should not be lulled into a sense of false security by changes in international relations or reform at home. The West is still spending more on intelligence than Moscow, he said.

"Foreign spies cost us millions of rubles, and dozens of agents have been unmasked in recent times, some of them, regrettably, Soviet citizens," he said.

"The five years of perestroika show that socialism and democracy need protection. We believe it is our most important task to thwart the criminal activity of instigators and extremists." He made no mention of Kalugin's allegations.