Chinese officials Friday approved the death penalty for some drug and pornography cases, and they replaced the security chief who failed to quell last year's pro-democracy movement.

Wang Fang, the 70-year-old public security minister in charge of the police, submitted his resignation before Friday's meeting of the Standing Committee of China's legislature, the official Xinhua News Agency reported.He was replaced with Tao Siju, 55, who was vice minister of public security since 1988. Tao's ascendancy was predicted after he accompanied Communist Premier Li Peng on a tour of four Asian countries earlier this month.

The report gave no reason for the departure of Wang, who served in the post since 1987.

But as early as last year Chinese sources said Wang was expected to step down in disgrace for his failure to keep last year's pro-democracy marches by Beijing college students from escalating into a nationwide mass movement.

Police were ordered to block the initial student marches but failed, sometimes offering only token resistance. Some uniformed police flashed V-for-victory signs to show support.

The government finally called the army into Beijing's Tiananmen Square on June 4, 1989, causing hundreds of deaths.

The 135-member Standing Committee, which concluded a nine-day session Friday meets between annual sessions of the full 2,700-delegate National People's Congress.

Xinhua said the new drug law approved by the committee specifies sentences ranging from 15 years in prison to the death sentence for ringleaders of drug smuggling gangs and those linked to international rings. It also calls for sentences of seven years to life for possession of 2.2 pounds of opium or 1.75 ounces of heroin.

Drug abuse in China, while still far below Western levels, has increased in recent years along with income levels. A growing problem is the shipment of drugs from Southeast Asia through China to Hong Kong.

The committee mandated life imprisonment or execution for "serious cases" of producing or selling pornographic materials, but Xinhua did not say what would constitute a serious case.

"The resolution is aimed at safeguarding social order and promoting advanced socialist culture," Xinhua said.

China already allows judges to hand down the death penalty for virtually any crime if they deem the circumstances serious enough, and hundreds are executed annually, based on media reports alone. Official totals are never released.

Also Friday, Zheng Tuobin, 66, minister of foreign economic relations and trade since 1985, resigned and was replaced by his vice minister, Li Lanqing, Xinhua said. No reason was given.

Western diplomats, however, said they were told earlier in the year that Zheng was ill. He was not believed to be in political trouble.

The diplomats described his successor, Li, 58, as a pragmatist who worked in the auto industry and has experience in administering state loans and foreign investment. He speaks English and Russian.