Four Chadian men sentenced to death for the murder of a Sudanese businessman were executed by firing squad in the Chadian capital N'Djamena on Thursday, human rights activists said.
Another three convicted murderers were killed at the same time in N'Djamena, while a fourth was shot dead in the eastern town of Abeche, international news agencies said.
It was the first official execution to take place in the land-locked central African country since 1991 and was immediately condemned by the Chadian League of Human Rights (LTDH).
Dobian Assinger, the president of the human rights group, told IRIN by telephone that the first four men were sentenced to death on 25 October after a three-day trial and were denied the right to appeal.
President Idriss Deby ignored a plea to commute the sentences which was sent to him by human rights activists and lawyers on 30 October, he added.
Assinger said: "We were surprised to be learn yesterday that they would be executed today. Why was the execution performed so fast, while the defence were trying to appeal the sentence?"
"The courts should have followed the right procedure and allowed an appeal," he added.
The four were convicted of murdering Sheik Ibn Oumar Idriss Youssouf, the head of Chad Petroleum Company, in September.
Youssouf's company was set up recently to build a refinery on the small Sedigui oilfield north of Lake Chad to provide petroleum products for domestic consumption.
Those executed included a former official in the Chadian presidency, who was the alleged mastermind of the plot, and a former director of the Chad Petroleum Company.
The murder took place less than a month after the official inauguration of a much larger US $3.7 billion project to export 225,000 barrels of oil per day from the Doba oilfields of southern Chad along a 1,070 km long pipeline to a tanker loading terminal in neighboring Cameroon.
The project, led by US oil giant Exxonmobil, is expected to generate an annual income of US $80 million for Chad and $20 million for Cameroon over the next 25 years.