Inspector General, Pakistan's Punjab province, confirmed it was a suicide attack. Initial reports indicate the bomber was a very young man.
The bomber had been stopped at the gates of the parade ground, where people had gathered and then he detonated the bomb, reports news agency Press Trust of India, quoting Inspector General of Punjab Police Mushtaq Sukhera.
The casualties are mostly civilian - three Pakistani Ranger personnel have been killed and five have been injured. A family of eight is among the deceased.
The blast took place at 6:12 PM outside the parade ground near the Wagah border, 500 metres from the Indian side. Hundreds come to watch the ceremony at sunset and the victims, on Sunday, were on their way back when the attack took place.
The injured are being treated at the local hospitals -- the Ghurki Hospital, the Services Hospital and the Shalimar Hospital. 48 bodies were taken to the Ghurki Hospital, its Medical Superintendent confirmed.
Sources said there was an alert about a possible suicide attack 15 days ago, after which security was strengthened on both sides of the border. The Pakistan Rangers had put up extra barricades and stationed more personnel, as had the Border Security Force, which mans the Indian side of the border at Attari.
Sources in the BSF told NDTV that a communication from the Pakistan Rangers said the attack was earlier mistaken for a cylinder blast at a local restaurant.
The ceremony at the Wagah-Attari border is one of the longest in operation between India and Pakistan. It had continued largely untouched by the many ups and downs in the relationship between the two countries, including the recent ceasefire violations at the border.
But now, for three days starting today, no beating retreat ceremony will be held at the Wagah border at the request of Pakistan, said BSF chief DK Pathak.