Northeast China's Liaoning province has become the first province in the country to make lethal injection the standard practice for all its death penalty convicts.

The Higher People's Court of Liaoning announced on Wednesday that all cities in the province have adopted the method, which means execution by gunshot will no longer be used.

"Lethal injection can reduce the fear and suffering experienced by criminals," the court said in a statement on its website.

"It can also help preserve the body of the convicts after death.

"It is a symbol of the progress of civilization, and it also serves to punish criminals."

A number of cities in Liaoning have already set up lethal injection rooms, while others have acquired execution vehicles -- buses that can be sent, when required, to areas with fewer death penalty cases.

"At present, many countries still have the death penalty, and most of them adopt execution by shooting," said Zuo Lianbi, deputy president of the higher court of Liaoning.

"China and the United States are the only two countries that specify lethal injection as a legal execution method," he said.

Meng Xianfeng, an official from the higher court, said the blood of convicts will stop flowing 45 seconds after lethal injection, and the heart will stop beating.

"Criminals have no pain, no convulsion and no obvious change of facial expression during the whole process," he said.

The court also said it will formulate a strict system to ensure the procedure for practicing lethal injection is proper.

In 1997, China added lethal injection as an alternative method of execution, yet with no specific explanation on what kind of criminals should be executed by either of the methods.

In March that year, the Kunming Intermediate People's Court in Yunnan province carried out the first execution through lethal injection in the country.

A survey by the Supreme People's Court, China's top court, shows that all criminals chose lethal injection over shooting when asked which method of execution they prefer.

In 2001, the top court required wider use of lethal injection and a dozen cities across the country are now moving in Liaoning's direction.

The Beijing and Chongqing municipal governments have announced that they will fully practice lethal injection by next year.

Wang Dawei, a professor with the Chinese People's Public Security University, is one of those who believes lethal injection will replace execution by gunshot.

"The faster the method and the less pain it brings to criminals, the more chance the method will be adopted," Wang said.

"The wider adoption of lethal injection is a symbol of democracy and civilization as it is the last form of respect for life."