Pakistani military spokesman, General Asim Saleem Bajwa, said on Friday that security forces have concluded the gunmen who killed 29 people in the northwestern city of Peshawar, including 16 worshipers at a mosque, earlier in the day "came from Afghanistan".
The attack on a Pakistani military base triggered an hours-long firefight and Pakistani forces said they killed 13 of the attackers, though it was unclear how many were involved in the assault.
As well as 16 worshippers killed inside the mosque, 13 air force and army employees at the base were also killed by the militants.
According to Bajwa: ""The conclusion we draw from the (intercepted) conversations is that the attackers came from Afghanistan. This operation was planned in Afghanistan, controlled and executed from Afghanistan."
The attack was a major blow to Pakistan's military, which had stepped up operations against militants following a Taliban attack last December at a Peshawar school that killed 150 people, mostly children.
It also underscored the ability of the militants to stage large attacks on targets linked to the country's military and government.
"I would hope that the state (Afghanistan) will absolutely not take part in such actions and the way we and Afghans are brothers, I absolutely would not expect this and no Pakistani can even think that our Afghan brothers, the Afghan government or the state could encourage this sort of thing," he said.
Pakistan media reported that Pakistani officials said the attack started at around 5 am. The assailants split into two groups after they entered the base, using rocket launchers and grenades, and targeted the administrative and technical areas of the base.
One group of militants attacked a mosque, officials said. Seven people were killed in a barracks next to the mosque that was used as an ablution area, and 16 people were killed inside the prayer room as people awaited the dawn call to prayer, Bajwa said.
He said a quick reaction force reached the base within 10 minutes of the attack and successfully engaged the militants.
Pakistan launched a military offensive, "Operation Zarb-e-Azb," against Taliban militants in the north Waziristan tribal region last year in June. The military claims to have wrested most of the region from the militants, and fighting is continuing in Shawal, a thickly forested area near the Afghan border. But even as the number of terrorist attacks in Pakistan has dropped since the offensive began, the attack on Friday underlined the continued threat from militants.
"Such sporadic attempts can take place in a state of war," Bajwa said.