Manhunt
Police are searching for two men who jumped off the Samjhauta Express shortly before the bombs detonated, sparking a fire that engulfed two coaches. Sketches of the two men were released on Tuesday.
"It is a terrorist act, we should condemn this act with unity"
Farzan, Hyderabad, India
"Investigations are in a preliminary stage. There have been no arrests so far," Arora said.
A Pakistani national, Usman Mohammed, who had thrown one of the suitcase bombs off the train and had been held for questioning, was cleared of suspicion and released to the Pakistani mission in New Delhi, he said.
Delhi police said on Wednesday they were investigating a suspicious phone call made to Pakistani-administered Kashmir just after the bombs exploded, indicating the possibility of a Kashmiri separatist hand in the attack.
Relatives have identified 33 of the 68 badly burned corpses - 27 Pakistanis and six Indians, said foreign ministry spokesman Navtej Sarna.
The bodies of 12 Pakistani nationals were taken home early on Thursday, including the remains of six members of the same family whose funeral drew thousands of mourners in Karachi.
India and Pakistan have said they would not allow the attack to undermine their peace process, and New Delhi has agreed to share information from the investigation through a joint panel formed last year to fight terrorism.