MOSCOW, November 3 (RIA Novosti) - The driver employed by Russian-Israeli businessman Shabtai von Kalmanovich, who was shot dead in central Moscow on Monday, is in a grave condition, a hospital source said on Tuesday.

Unidentified assailants armed with a 9mm automatic and a pump-action shotgun opened fire at fifty-nine-year-old Kalmanovich as he sat in his black Mercedes S500 on Moscow's Krasnopresnenskaya Embankment at about 4:50 p.m. Moscow time (1:50 GMT). He died instantly.

His driver, who initially tried to give chase, was forced to pull over outside the capital's 16th century Novodevichy Convent due to serious injuries. He was later taken to a Moscow clinic where he underwent surgery.

"Pyotr Tumanov is in intensive care after surgery - his condition can be assessed as grave," the hospital source said, adding that security had been tightened in Tumanov's ward.

Russian prosecutors said earlier in the day that the driver was stable after surgery.

Investigators have said the attack bears all the hallmarks of a contract killing. They have also not ruled out that the murder was linked to Kalmanovich's business activities.

Born in 1949 in Soviet Lithuania, Kalmanovich left the U.S.S.R. with his family for Israel in 1972, where he graduated from Jerusalem University. In 1988, he was sentenced to nine years in jail for spying for the Soviet Union, but released in 1993. He then left Israel and returned to Moscow, quickly finding his way in the chaotic dawn of post-Soviet capitalism.