Pakistan's Punjab government said on Monday the involvement of a "foreign hand" could not be ruled out in the Wagah border suicide bombing, even after three homegrown militant factions separately claimed responsibility for the attack that killed at least 61 people.
"Foreign hand cannot be ruled out in the Wagah Border suicide attack," Punjab interior minister Col (R) Shujah Khanzada told reporters.
"The suicide-bomber wanted to blew himself up at the Parade Avenue. Had he succeeded a ground would been prepared for action against Pakistan by the international forces. This is why some foreign hand seems to be behind this incident," he said.
Khanzada said the government has formed a joint investigation team to look into the "aspects of the attack." He also criticised security lapse by Pakistan Rangers.
"The Punjab government was not responsible for the security of the Wagah border. It is an exclusive domain of the rangers."
He said all law enforcement agencies have been put on red alert to foil any terror attack in the country.
At least three militant factions have claimed the grizzly bombing. Al Qaeda-affiliated militant group Jandullah -- a splinter group of the Tehreek-i-Taliban Pakistan (TTP)-- was the first to claim responsibility of the attack.
Shortly afterwards, Jamaatul Ahrar said its bomber Hafiz Hanifullah carried out the attack. And later a lesser-known Mahar Mehsud group also claimed responsibility.
Asked about the involvement of any of these groups in the attack, Khanzada said: "The investigation will bring forth who is involved in the attack."
Meanwhile, intelligence agencies this evening arrested two more suspects from Lahore and shifted them to an undisclosed location for investigation.
"We have arrested two terror suspects from Lahore and also recovered a suicide vest from a fruit truck entering Lahore from Peshawar," a senior Lahore police officer told PTI.
At least 61 people including, 10 women, eight children and three security personnel were killed when a suicide-bomber blew himself up near the main gate of Wagah Border Parade Avenue on Sunday.
Pakistan, however, allowed on Monday general public to view the popular flag-lowering ceremony at Wagah Border, hours after cancelling it.