India and Pakistan have held a daily military ceremony at their main border crossing, a day after a suicide attack there killed 55 people and wounded dozens more.
The two countries pressed ahead with the ceremony at Wagah on October 3, despite earlier plans to suspend the event.
The bomber struck at Wagah near Lahore on October 2 as hundreds of people were returning from the military parade.
Pakistani Prime Minister Nawaz Sharif expressed "grief and sorrow" over the attack.
His Indian counterpart, Narendra Modi, condemned the "shocking" and "dastardly" bombing.
A doctor at a local hospital said that there were 10 women and seven children among the dead, and eight members of a single family.
Footage on Pakistani news channels showed people covered in blood and crying in pain as they were evacuated to hospitals.
According to RFE/RL's Radio Mashaal, several Taliban splinter groups claimed responsibility, including Tehrik-e Taliban and Jamat-ul-Ihrar.
A spokesman for Jamat-ul-Ihar, Ehsanullah Ehsan, said in a statement sent to media that the attack was revenge for those killed in the Pakistan Army campaign against militants in the tribal areas of North Waziristan.
According to the Pakistani military, some 1,200 insurgents have been killed since the military launched the offensive in mid-June.
Security has been increased across Pakistan to thwart possible attacks on minority Shi'ite Muslims observing Ashura, which marks the death of Imam Hussein, the Prophet Muhammad's grandson and one of the most revered figures in Shi'ite Islam.