IMPHAL, NOV 3: An indefinite curfew was clamped today in Imphal and Greater Imphal area following yesterday's incident in which 10 persons were killed during an exchange of fire between Assam Rifles personnel and armed ultras, official sources said here.Sources said the government clamped curfew after it received reports that there was likelihood of serious breach of peace, disturbance to public tranquility and grave danger to human lives and properties in the two districts.Security measures have been tightened throughout the two districts following reports that some anti-social elements were likely to indulge in unlawful activities, sources said.Police personnel were asking people to stay indoors through the public address system.Meanwhile, bodies of all the 10 persons, including a woman killed in yesterday's incident, were lying at the morgue of the Regional Institute of Medical Science Hospital for post mortem, sources said.Sources said four of the victims identified were - a school teacher, a government employee, a goldsmith and an old villager. The rest are yet to be identified.Sources said 10 persons were killed yesterday during a crossfire between Assam Rifles personnel and armed ultras following the explosion of an underground-planted powerful bomb at Malom Tulihal area on Imphal airport road.An Assam Rifles statement said two jawans were also injured in the incident and one M16 rifle and magazine of an AK 47 rifle recovered from the spot.