A bomb has exploded at a railway station in India's north-eastern state of Assam, which is preparing to host the country's national games.
Violence has escalated in Assam since September
There were no casualties in the explosion at the Kamakhya railway station in the main city of Guwahati.
No group has so far said it carried out the attack.
Earlier this week, the separatist United Liberation Front of Assam (Ulfa) withdrew a planned boycott of the games on the request of some top athletes.
Ulfa is fighting one of India's longest-running insurgencies to establish an independent homeland in Assam.
The head of India's ruling Congress party, Sonia Gandhi, is due to open the country's 33rd national games in Guwahati.
More than 7,000 athletes and officials have gathered in the city for the event.
"The explosion was powerful, but with no passengers around the place a possible disaster was averted," senior police official Rajen Singh told the AFP news agency.
"We are not sure who was behind the explosion," he said.
There has been an upsurge in violence in Assam in recent months with officials pointing to the role of Ulfa.
The group has been blamed for a number of bombings and shootings in which about 90 migrant workers were killed.
The group, however, has said it would not disturb the national games.