A massive police hunt is underway in the southern Indian city of Bangalore for a gunman who escaped after shooting dead a college professor.
Police are on high alert across Bangalore
Four others were wounded in the attack on Wednesday during a major conference at the Indian Institute of Science.
Professor MC Puri, from the Indian Institute of Technology Delhi, died on his way to hospital.
The state's chief minister has blamed "terrorists" for the attack, but it is still not clear who was behind it.
No motive has so far been established and no group has said it carried out the attack.
Checkpoints and barricades have been set up across the city and cars and other vehicles are being searched.
The BBC's Habib Beary in Bangalore says there is a heavy security presence at railway stations, roads and airports and police have been conducting searches across the city.
Other science and research institutes elsewhere in India have been put on high alert.
Dharam Singh, chief minister of Karnataka state of which Bangalore is the capital, said the attack appeared to be "pre-planned terrorist activity", carried out by up to three people. He did not name any group.
"The intention is to create fear and demoralisation," he told reporters after emergency security talks.
"They are terrorists and we are trying to identify who they are."
Police believe the attack on the conference, attended by about 300 delegates from Indian and abroad, was aimed at getting international publicity.
Bangalore is home to more than 1,500 information technology companies, many of them global, accounting for a third of India's software exports.
State police chief BS Sial said he could not rule out the involvement of foreign-based militants but that no direct evidence or reason for the attack had yet been uncovered.
He said the city was clearly a soft target and called on the IT sector to help pay for improved security.
Mr Sial said he saw no reason to link the shooting with the arrival in the city of the gangster Abu Salem.
He was brought by police to Bangalore for lie detector tests over his alleged involvement in bombings in Mumbai (Bombay) in 1993 that killed 250 people.
Witnesses said the gunman sprayed gunfire from an automatic weapon at scientists and laboratory technicians attending the conference before escaping in a car.
The Indian Institute of Science is a premier research institute
"It was like crackers exploding. Suddenly I saw one man falling," a security guard told the AFP news agency.
The Indian Institute of Science is India's premier scientific research institution and a leading postgraduate college in India's technology hub of Bangalore.
Police say they have recovered an AK-56 gun from the site of the shooting and defused a live grenade.
Police say the four scientists injured in the attack are recovering in hospital.
One of the injured, Prof Vijay Chandru, is the founder of the Indian-developed palm-computer, the Simputer. His condition is reported to be stable.
Meanwhile, the family of retired professor MC Puri are arranging for his body to be flown back to Delhi.