A Kashmiri man convicted over the 2001 attack on India's Parliament has been hanged after a final mercy plea was rejected.
Home secretary RK Singh said: "It was the law taking its course."
Guru was convicted by India's top court in 2002, and a mercy petition sent to India's president, the last step in the judicial process, was turned down earlier this week.
Several rights groups including political groups in Indian Kashmir have said that Guru did not get a fair trial.
Government prosecutors have said that Guru was a member of the militant group Jaish-e-Mohammed, a charge he denied.
Thousands of police and paramilitary troops were fanning out across Indian Kashmir preparing for any protests and violence that might break out following the announcement of the execution. A curfew was also imposed in the Himalayan state.
Six security troops and a gardener were killed in the December 2001 attack. All five men who launched the attack were also killed.