MOSCOW, Oct 27: A KGB master agent who ran some of Moscow’s most damaging Cold War spies in the West – Klaus Fuchs and the Rosenbergs – died on Friday after a lifetime of espionage that helped the Soviet Union acquire the nuclear bomb.

Alexander Feklisov, who also played a key role as a mediator in the Cuban Missile Crisis, was 93, a spokesman for Russia’s foreign intelligence service (SVR) said.

He arrived in New York in 1941 and began running Julius and Ethel Rosenberg, a married couple who supplied the Soviet Union with top secret information on the US Manhattan project to develop the atomic bomb.

Feklisov later called the Rosenberg network one of the greatest in the history of Soviet espionage. The Rosenbergs were executed in 1953.

“Feklisov made an important contribution to the activity of Russia’s foreign intelligence network in New York on nuclear issues,” a spokesman for the foreign spy service was quoted as saying by Interfax news agency.

“He conducted serious missions related to the procurement of secret scientific and technical information, including in the area of electronics, radiolocation and jet aircraft technology,” the spokesman said.

In his autobiography, “The Man Behind the Rosenbergs”, Feklisov recounted how he had played Le Carre-style espionage games to throw off US minders in New York. He said he ran a total of 17 foreign agents in his lifetime.

After working the Rosenbergs, Feklisov returned as a silent hero to Moscow. But he was quickly dispatched to London in 1947 as deputy chief of intelligence operations for science and technology.

He soon made contact – in a London pub – with Fuchs, a German-born scientist who worked at the US atom bomb project in Los Alamos and at Britain’s Harwell nuclear research laboratory.

Fuchs passed on secrets that helped speed Moscow’s race for the nuclear bomb by at least 18 months, intelligence officials said later when the extent of Fuchs’ treachery was examined.

“Feklisov was in contact with Klaus Fuchs, who provided important nuclear information, including on the structure of the hydrogen bomb,” the SVR spokesman said.—Reuters