Amritsar, Nov 2 (IANS): Border Security Force (BSF) troopers were put on high alert along the India-Pakistan international border Sunday evening after a massive blast left over 45 people dead and over 70 others injured at Wagah in neighbouring Pakistan.

The dead include men, women, children and Pakistan Rangers troopers. Most of them were returning from the Wagah border retreat ceremony.

BSF officials at Attari border in Punjab said that the blast was heard at a distance of nearly two kilometres.

Security officials in Pakistan said that the blast was suspected to be carried out by a 'fidayeen' (suicide bomber).

The blast, according to information obtained by the BSF, took place close to the place where the Retreat ceremony takes between troopers of both countries to mark the closure of the border gates in the evening. Attari is about 30 km from Amritsar.

Being a Sunday, the rush of visitors for the Retreat ceremony on the Pakistan side was also higher than normal days, BSF officials said.

"We have put our troopers on high alert along the entire border following the Wagah incident. We are trying to get details," a BSF official said.

Officials said the death toll was likely to go up.

The incident took place at 5.50 p.m. local time in a restaurant near Wagah border area in the outskirts of Lahore. At the time of incident, many people were in the restaurant for food, the reports said.

Initial reports said the explosion took place due to gas cylinder blast, but police did not confirm it.

Rescue teams, police and security forces rushed to site and shifted the bodies and injured to the nearby hospital.