A harsh new law mandating death for anyone found with small amounts of drugs take effect in Iran Saturday, part of a ferocious crackdown in which scores of smugglers have already been executed.

The law make the death sentence mandatory for people convicted of possessing 30 grams, or just over an ounce, of heroin, codeine or morphine or smuggling 11 pounds of opium or hashish. Simple possession of opium or hashish carries a jailterm.It is the toughest crackdown since the early days of the Islamic revolution, when hundreds of alleged drug users and pushers were rounded up and executed.

The new campaign followed the Aug. 20 cease-fire in the Iran-Iraq war and an alarming surge in drug abuse blamed in part on hardships caused by the 8-year-old conflict.

Iran's Chief Justice, Ayatollah Musavi Ardebili, blamed the drug problem on Tehran's enemies.

"The problem . . . is a political one," he said recently. "The superpowers, just as they fought the Islamic revolution on the battlefield and in the economic field . . . use narcotics as one method to battle with the people . . . and taint the revolution."

Even before the new law came into force, Iranian authorities had rounded up more than 1,000 suspected smugglers and pushers, running them through Islamic tribunals and hanging them as soon as they were found guilty.

On Jan. 7, 19 smugglers were hanged or shot by firing squads.

Nine days later, Iran's official media said 56 were executed in one day in various cities, a chilling display of Tehran's determination to eliminate drugs.