A bomb exploded near a luxury train waiting lounge at the main railway station in the eastern Pakistan city of Lahore on Tuesday, killing at least two people, police said.
"It was a bomb blast, two people have been killed and 10 injured," senior police officer Abdul Razzaque Cheema said.
Rescue official Kiramat Ali described it as a ‘huge blast’ and said 35 wounded had been taken to hospital.
Pakistan suffers frequent attacks blamed on Taliban and Al-Qaeda-linked militants, who are most active in the lawless tribal belt in the northwest of the country on the border with Afghanistan.
The explosion was the first attack in Lahore, regarded as Pakistan's cultural capital, since a bomb at a Sunni Muslim shrine in February 2011, which killed two people.
A photographer at the scene said the blast took place near the lounge for the luxury Business Express train to Karachi, a service launched two months ago offering first-class travel between Pakistan's two biggest cities.
Television footage showed a waiting room littered with glass and upended furniture, its windows blown in by the force of the explosion.
Senior police officer Ali Ahmad Malik said the bomb was left in a bag and the dead were a porter and a policeman. He added the Business Express train had left the station and was not the target.
City police chief Aslam Tarin told reporters at the site that six to eight kilograms of explosives were used in the bomb.
"It was an act of terrorism and we are investigating how the terrorist came inside the railway station," he said.
Islamist militants have killed more than 4,900 people across Pakistan since government troops raided an extremist mosque in Islamabad in July 2007.