"We suggest the higher court reject their appeal for lenient sentences and uphold the previous verdict," the Yunnan provincial prosecuting department said at the hearing on Thursday.

In November, during the trial in Kunming, Naw Kham and the other gang members initially denied plotting the sailors' murders, but changed their pleas to guilty near the end of the trial and asked for lenient sentences.

They were charged with intentional homicide, kidnapping, transporting drugs and hijacking cargo ships, or a combination of those offenses. The court ordered them to compensate the victims' families 6 million yuan ($963,000).

Because of his guilty plea, Naw Kham did not expect to receive the death sentence, said Lin Li, his lawyer.

"He is willing to sell his private property for 6 million yuan to compensate the victims' families, and I think it's better to combine punishment with education, and give a lenient sentence," Lin said.

Yang Duoxu, the wife of Wang Guichao, one of the murdered sailors, said she hopes more arrests will be made.

"I really hope Chinese authorities will soon arrest the nine Thai soldiers who were involved," Yang said.

"I feel like the sky is falling, and I am caught in a living death," she said.

"My husband and I had been working on the cargo ship for more than 10 years. He earned 5,000 yuan a month, and I was a cook earning 3,000 yuan a month. Now I don't have the money to support my three children."

Nie Tao, director of the legal department under the Yunnan Public Security Bureau, said they are working to bring the Thai soldiers to justice.

"Thai police and prosecuting departments are stepping up efforts to speed up the legal processing of the nine Thai soldiers who colluded with Naw Kham's gang to plot the murder," Nie said.

"We are intensifying judicial operations with Thai police, and providing them with the evidence of the Thai soldiers' crimes," he said.

The gang's denial of the murders is aimed at delaying their execution, according to Hong Daode, law professor at China University of Political Science and Law.

"If sentenced to death, the local courts will refer the sentence to the Supreme People's Court for review, and after approval, it will be carried out," Hong said.

"There is no question the court should sentence them to death," he said. "The six criminals, headed by Naw Kham, used cruel means to illegally deprive other people's lives, and the consequences were serious."