ISLAMABAD, June 7: The United States had provided Pakistani authorities intelligence about involvement of North Waziristan-based militants in the April 15 attacks in Kabul. Upset over Pakistan’s alleged inaction against those groups and identified targets, the US acted directly, pounding them with drones.

A piece of information shared with Dawn by military and intelligence sources may explain the sudden spike in drone attacks in recent weeks. The CIA carried out six drone strikes last month against an average of three per month this year.

The pattern is said to have continued with three attacks just in the first week of June, one of which took out Al Qaeda No 2 Abu Yahya Al-Libi in Mirali.

Sources aware of the intelligence sharing between Pakistan and the US on the Kabul attacks said the sites where the improvised explosivedevices were suspected to have been manufactured were identified in the information.

The IED factories pointed out by the Americans were in North Waziristan.

Additionally, the US is said to have presented evidence of involvement of not only the Haqqani network and Taliban but also collusion of some of their Pakistani affiliates.

Because of the sensitivity of the issue, the sources would not say when and at what level was the intelligence shared with Pakistan.

About Pakistan’s reaction, they said the concerns were noted, but at the same time officials appeared hesitant in accepting that groups based in North Waziristan were involved in the attacks.

There hadn’t been any appreciable action by the Pakistani side, one of the source said, adding that “the US acted against some of those targets using drones”.

Military spokesman Maj Gen Asim Saleem Bajwa was unavailable for comment.

An army officer, who was not authorised to speak on the issue but has been aware of the intelligence cooperation between Pakistan and the US, rejected the allegations.

Pakistan has consistently maintained that the drone strikes are illegal and violation of its sovereignty and territorial integrity. Parliament has demanded cessation of drone strikes.

US chargé d’ affaires Richard Hoagland was earlier this week summoned to the Foreign Office and a protest note on drone attacks was handed over to him.

The April 15 attacks in Kabul led to hardening of the US stance on Pakistan. The incident not only made the Obama administration to go back on its promise of apologising on the Salala attack, but also caused it to get tougher towards Pakistan, particularly in negotiations onnew terms of engagement.