Three men convicted in connection with the 1991 assassination of former Indian Prime Minister Rajiv Gandhi are to be hanged on September 9, 2011 officials say.
They will be hanged in the early hours of the morning, an official at the prison where they are being held in the Indian state of Tamil Nadu said.
The move comes after India's president rejected mercy pleas from the men known as Murugan, Santhan and Perarivalan.
The killing of Rajiv Gandhi by a Tamil Tiger suicide bomber shocked India.
All three of the condemned men were members of Sri Lanka's Tamil Tigers militant group and were convicted of plotting the assassination. Murugan and Santhan are from Sri Lanka and Perarivalan is an Indian Tamil.
In 2006, the Tamil Tigers expressed "regret" for the murder.
The Supreme Court in 1999 confirmed the death sentences of the three men, but commuted capital punishment to life imprisonment for Nalini Sriharan, an Indian Tamil woman married to Murugan who was also convicted in connection with the assassination.
"The three convicts are personally informed that today that they will be hanged," Mr Pugazendhi, a lawyer representing the three men, told the BBC Tamil service.
He said they had expected the chief minister of Tamil Nadu state to make a personal intervention.
"As there is no sign regarding political intervention, we are exploring other legal options," he said.
The mother of Perarivalan also told BBC Tamil that he denied the charges and said that she believed the judgement was based on a forced confession.
The death penalty is rare in India. The last execution was in 2004 when a 41-year-old former security guard was hanged for the rape and murder of a 14-year-old schoolgirl. (Source : BBC)