NEW DELHI: Four bandits sentenced to death over a landmine blast that killed 22 policemen in 1993 approached India's Supreme Court on Saturday in a last-ditch bid to escape execution, a lawyer for the men said.

The four accomplices of slain sandalwood smuggler Veerappan were scheduled to hang on Sunday after Indian President Pranab Mukherjee rejected their mercy plea, according to the convicts' lawyer, who spoke to AFP on condition of anonymity.

But a senior prison official where the four convicts were being held said no immediate preparations were underway for their hanging.

“I have filed a request for an urgent hearing later today (Saturday) at the Supreme Court, asking for a stay on their execution,” the lawyer for the convicts said.

“We are asking for their sentence to be commuted to life imprisonment because of the mental distress suffered by them while waiting eight years for a decision on their mercy plea,” he added.

“No preparations are going on for the execution of the four convicts tomorrow (Sunday). We are awaiting instructions from higher authorities,” said a senior official at Belgaum jail, where the four men are being held.

The official spoke on condition of anonymity.

Local media reports said that jail authorities would need at least a day to prepare for the executions.

The four men were sentenced to death in 2004 for their role in a landmine explosion in the southern state of Karnataka that killed 22 policemen and injured 11 others.

Veerappan, the leader of the gang, who was accused of more than 100 murders and abductions of high-profile politicians and actors, was shot dead in a police ambush in the jungle the same year after evading capture for 18 years.

Executions are only carried out for “the rarest of rare” cases in India.

But recently elected president Mukherjee has rejected a number of mercy pleas in the last few months, ending an eight-year-long informal reprieve.

Last weekend Afzal Guru, a Kashmiri separatist convicted of involvement in a deadly 2001 attack on the Indian parliament, was executed in New Delhi, triggering angry protests in the disputed region of Indian-administered Kashmir.

The sole surviving gunman from the 2008 Mumbai attacks, Pakistani-born Mohammed Ajmal Kasab, was hanged on November 21 last year, in the first execution in the country since 2004.