Terrorists shot and killed former Turkish premier Nihat Erim early today at his vacation home near Istanbul, police said. A note found at the scene claimed an extreme leftist group was responsible.

Erim, 68, headed the Turkish government between 1971 and 1973 and presided over a severe martial law crackdown of the Turkish left. He was a former member of the left-of-center Republican People's Party, now headed by former premier Bulent Ecevit.

Police sources said one of Erim's bodyguards also was killed in the terrorist attack. Erim's wife was with him but escaped unhurt, police said.

Erim's assassination followed the slaying of a Republican Party member of parliament Tuesday. Abdurrahman Koksaloglu, shot to death by two gunmen in an Istanbul street, was buried after a state funeral Friday.

Washington Post special correspondent Metin Munir reported that the two murders represent a new and sharp escalation in Turkish terror, which is now claiming 10 lives a day.

For nearly half of his life Erim was a leading figure in politics and law in Turkey. He held two Cabinet posts soon after entering parliament in 1945. He drafted the treaty and constitution under which Cyprus won independence from Britain in 1960.

In 1971 the Turkish generals ousted Suleyman Demirel (who currently is prime minister) and turned to Erim to lead the country.

In 1971 Erim banned the cultivation of opium under pressure from the Nixon administration, which claimed that 80 percent of the heroin that entered the United States illegally every year originated from Turkish poppy fields. The ban was lifted by Ecevit in 1974.

The police sources said Erim was shot several times in the chest and that his bodyguard died on the way to hospital. Quoting the witnesses, police said four gunmen "all in their late teens or early twenties" took part in the killing. The gunmen reportedly fled in a waiting car.