KUNMING - Naw Kham, principal suspect for the murders of 13 Chinese sailors on the Mekong River last year, pleaded guilty Friday evening when he and five other people were standing trial in southwest China.

The trial, which opened Thursday morning at the Intermediate People's Court of Kunming, capital of Yunnan Province, ended on Friday, one day ahead of schedule.

Naw Kham, the head of an armed drug gang from Myanmar, expressed his penitence to the victims and their families in court, hoping for leniency.

The court will pick a date for sentencing following a review of the case by a collegiate bench.

Naw Kham denied plotting the attack on Thursday. However, the five other defendants on trial all testified in court that Naw Kham was the gang's ringleader who masterminded the attack.

The six suspects were charged with intentional homicide, drug trafficking, kidnapping and hijacking by the Kunming People's Procuratorate.

Prosecutors showed irrefutable and sufficient evidence of the criminal offences, including the six defendants' confessions, witness testimonies, DNA test results, and autopsy reports.

Thirteen witnesses from Laos and Thailand testified in the trial on the basis of bilateral judicial assistance treaties between China and the two counties respectively. They were protected by the court according to China's law and international practice.

All six defendants who were foreigners answered questions raised by the chief justice, judges, prosecutors, victims' relatives and lawyers during the trial, aided by translators.

Relatives of the 13 Chinese victims, embassy personnel of the related countries, Chinese legislators, political advisors, experts and representatives of local residents and media were present at the court during the two-day trial.

The court also heard the trial of the incidental civil action of the case on Friday.

Victims wanted civil compensation of tens of millions yuan but the court did not reveal the exact figures.

Naw Kham did not deny the evidence provided by the prosecutors on Friday. He said he was willing to pay compensation, adding that he had 30 million baht (about 6 million yuan or $951,139).

Begging for lighter punishment, the other five defendants also pleaded guilty in court but said they had no money for compensation.

Nie Tao, a Chinese police officer with the special task force of the case, said police from both China and Thailand exchanged views on the nine Thai soldiers who were allegedly involved in the case on Friday afternoon.

Chinese police will continue to cooperate with the Thai police in the investigation into and prosecution of the nine Thai soldiers, Nie said.

The Naw Kham crime ring was busted earlier this year in a joint operation by police from China, Laos, Myanmar and Thailand after the brutal murders of the Chinese sailors triggered an outcry in China last year.

The 13 Chinese sailors were confirmed dead after two cargo ships, the Hua Ping and Yu Xing 8, were hijacked on October 5, 2011 on the Mekong River.

With a length of almost 5,000 km, the Mekong River, known in China as the Lancang River, is one of the most important waterways in Southeast Asia, linking the countries of China, Laos, Myanmar, Thailand, Cambodia and Vietnam. It plays a crucial economic role among the Greater Mekong Sub-region countries.