Mid-level militants and others have told The New York Times that increased U. S. drone strikes have taken a heavy toll on al-Qaida and Taliban militants in Pakistan.

It was further reported that the strikes operated by the U. S. Central Intelligence Agency in the North Waziristan tribal area have intensified since a December suicide attack on a CIA base at Khost in southern Afghanistan killed several agency employees.

The drone strikes have spread fear in a region where militants once roamed freely. Now, the militants have abandoned their satellite phones and avoid large gatherings, preferring instead to use couriers and move in small groups, The Times, quoting mid-level militants and supporters of the government, said.

The sources further said that the drones fly up to four at a time, observing and tracking targets before firing missiles on their targets.

Citing Pakistani and American accounts, it was further reported by the Times that up to 90 suspected militants were killed by the drone strikes in the first six weeks of this year.

A mid-ranking fighter associated with the insurgent network headed by Jalaluddin and Sirajuddin Haqqani, said, "It seems they really want to kill everyone (rank-and-file fighters), not just the leaders."

It was further elaborated by the report that the impact of the drone attacks is difficult to gauge as North Waziristan is virtually closed to outsiders.

It also said that some of the villagers in the region, fearing the drones might also target them, are no longer renting space to Arabs linked to al-Qaida.

However, it further said that the al-Qaida-supported Haqqani militant network also is linked to Pakistan's military and intelligence services, which Islamabad may use for influence when Americans leave Afghanistan. (With Inputs from Agencies)