In its annual report on executions, the rights group said about 1,770 executions were reported to have been carried out in China in 2005, but added the real figure was undoubtedly much higher, noting a Chinese legal expert had been quoted as saying the true figure was about 8,000.

More than 20,000 people were on death row around the world, said the report, which repeated a call for the worldwide abolition of the death penalty.

Amnesty said at least 2,148 people were executed in 2005 in 22 countries -- 94 percent of them in China, Iran, Saudi Arabia and the United States. That's down from 3,797 executions in 2004, but up from 1,146 in 2003.

"The death penalty is the ultimate, irreversible denial of human rights, because it contravenes the essence of human values, it is often applied in a discriminatory manner, follows unfair trials or is applied for political reasons," Amnesty International Secretary-General Irene Khan said in a statement.

At least 94 people were executed in Iran, 86 in Saudi Arabia and 60 in the United States.

"As the world continues to turn away from the use of the death penalty, it is a glaring anomaly that China, Saudi Arabia, Iran and the U.S. stand out for their extreme use of this form of punishment," Khan said.

China has carried out executions by shooting or lethal injection, Saudi Arabia by beheading, Iran by hanging or stoning and the United States by electrocution or lethal injection, Amnesty said.

Amnesty said its figures were approximate because of secrecy surrounding the death penalty. China refuses to publish official statistics on executions while Vietnam has classified statistics on the death penalty as a "state secret", it said.

But the rights group said with the addition of Mexico and Liberia, 86 countries had now abolished the death penalty for all crimes, compared with 16 countries in 1977, it said.

In China, a person can be executed for as many as 68 crimes, including non-violent crimes such as tax fraud, embezzlement and drug offences, it said.

Amnesty said Iran was the only country it knew of that had executed juvenile offenders last year. The United States outlawed juvenile executions in March 2005.

Iran executed at least eight people in 2005 for crimes committed when they were children, including two who were still under the age of 18 at the time of their execution, it said.