On Sunday evening, a suicide bomb attack at the Wagah checkpoint on the outskirts of Lahore and along the Indian-Pakistan border killed about 55 people and injured over 120, including women and children. The attack was the deadliest to hit Pakistan in a year.

Punjab Police Inspector General Mushtaq Ahmad Sukhera reported a suicide bomber set off his vest after a daily parade in a deadly attack at the border in Wagah, a Pakistani town on the border with India and near Lahore, the provincial capital of Punjab Province. In a CNN report, the inspector said it appeared the bomber entered the parade as people were leaving and detonate an explosive vest near the checkpoint.

"A large number of people were returning after watching Rangers flag ceremony at Wagah border when a suicide bomber blew him up near one of the exit gates," Punjab Police Inspector General Sukhera said. He also added three Pakistani Rangers were killed, as Hindustan Times reported.

Over 50 people have been killed and more than a hundred were injured in a suicide bomb attack near Lahore. BBC News reported two militant groups were claiming responsibility over the lethal blast. The Wagah crossing is a high-status target, with outsized crowds gathering every day to observe a highly structured flag-lowering ceremony as the border closes.

Spokespersons for the two militant groups associated to the Pakistani Taliban, Jundallah and Jamaat-ul-Ahrar, separately claimed responsibility for the suicide bomb attack on the outskirts of Lahore. Jamaat-ul-Ahrar spokesman Ehsanullah Ehsan called Jundallah claim unfounded. According to The New York Times, Ehsan vowed for more attacks to "the pillars of the infidel" now governing Pakistan.

"This is a continuation of our jihad for the implementation of an Islamic system in Pakistan. We will soon release the video of this attack," Ehsan's statement said. "This attack is the revenge of the killing of those innocent people who have been killed by Pakistan Army, particularly of those who have been killed in North Waziristan."

The suicide bomb attack on the outskirts of Lahore occurred in a car park on the Pakistani side at least 500 meters from the border with India. As reported by Reuters, no Indian troops were hurt and Pakistani police have cordoned the area and were investigating the attack.

Inspector General Sukhera reported the death toll has rapidly increased since the suicide bomb attack in Lahore was initially reported. He also added more than 5 kilograms or 11 pounds of explosives were used in the blast, which was orchestrated by an eighteen-year-old male. Some of the bomber's body parts were scattered at the scene.

The Indian and Pakistani leaders have expressed their thoughts on the attack. India has in the past accused Pakistan of sponsoring jihadist groups in the region. The two nations, which have fought three wars against each other, have been engaged in a long-running crisis over Kashmir region, which both sides claim.

Pakistani opposition politician Imran Khan described the suicide bomb attack on the outskirts of Lahore as an "act of terror."

"Shocked and saddened by suicide attack nr Wagah border killing over 50 innocent ppl incl women and children. Strongly condemn this act of terror," former global cricketer Khan tweeted.

Meanwhile, Indian Prime Minister Narendra Modi sent his condolences to the families of the deceased.

"Terror attack in Pakistan near Wagah Border is shocking. I strongly condemn such a dastardly act of terrorism," Modi tweeted.

Authorities were aware of the threats of terrorism. And for 55 years, Pakistani Rangers and Indian Border Security Force take part in the daily lowering-of-the-flags known as "beating retreat" ritual before sunset at the Wagah border crossing between Lahore and Amritsar, India. And because of the suicide bomb attack, the ceremony is postponed until Thursday.