BEIJING - China has issued new rules saying evidence obtained through torture and threats cannot be used in criminal prosecutions and said such evidence would be thrown out in death-penalty cases that are under appeal.

The new regulations, posted on the central government's website, make it clear that evidence with unclear origins, confessions obtained through torture, and testimony acquired through violence and threats are invalid.

It is the first time Beijing has explicitly stated that evidence obtained under torture or duress is illegal and inadmissible in court.

"Since the system was not perfect, the standards on reinforcing the law were not unified and the law executors were not equally competent," according to a statement on the website. "Problems occurred in the handling of cases and they should not be ignored."

The regulations were released jointly by the Supreme People's Court, Supreme People's Procuratorate, the Ministry of Public Security, the Ministry of State Security, and the Ministry of Justice, according to a statement on the website.

Legal experts in China say the new rules constitute major progress in protecting the legal rights of defendants.

One of the regulations pertains to how death-penalty cases should be reviewed, including a rule that illegally obtained evidence should be invalid.

A second rule sets out guidelines on how evidence should be obtained in criminal cases, which explicitly bans the use of force or intimidation on defendants and witnesses.

"The issue of illegally obtained evidence has long been a controversial one in China, and now they made a big step forward in this respect," said Fan Yu, a law professor at Renmin University Law School who specializes in the judicial system.

The rulings are especially important for death-penalty cases, where a flawed system has led to the deaths of several criminal suspects by torture in detention centers.

"Death sentences are irreversible," she said. "Any tiny mistake could cost people's lives. There's serious lesson to be drawn from those cases."

China executes more people annually than any country in the world, though it does not release an official count. The rights group Amnesty International estimated China put at least 1,718 people to death in 2008.

In 2008, China's top court said about 15 percent of death-sentence verdicts by lower courts were found to have problems, the China Daily newspaper reported Monday.