By M Ilyas Khan
BBC News, Islamabad
Militants have been torching supply bases in and around Peshawar
Pakistan's new security operation in the Jamrud area of the Khyber tribal region has come as something of a surprise.
Observers in the north-western city of Peshawar say that until Monday night there was no indication that troops were planning to move against suspected militant positions and "criminal elements" in the area.
Recent reports quoting unnamed military officials have said impending operations in the area had been postponed as troops had to be moved to the country's eastern border with India.
India has blamed a Pakistan-based militant group, Lashkar-e-Taiba, for last month's attacks in Mumbai that left more than 170 people dead.
Early this month, Pakistan said Indian fighter jets had violated its airspace a number of times, giving rise to fears that they might strike suspected militant targets in Pakistan.
Analysts say reports of the redeployment of Pakistani forces away from militant sanctuaries in the north-west had not gone down well with Western powers, notably the US, which is leading an international coalition of forces fighting militants in Afghanistan.
The latest operation in Khyber came just hours after a telephone call from US Secretary of State Condoleezza Rice to Pakistani President Asif Ali Zardari.
Ms Rice also spoke over the phone to India Foreign Minister Pranab Mukherjee.
Pakistan's Foreign Minister Shah Mehmood Qureshi said in a statement on Tuesday that Ms Rice's phone calls had helped lower tensions between India and Pakistan.
Indian officials have also made conciliatory noises during the past couple of days, lowering the temperature.
Analysts believe it is international, especially US, pressure that has pushed Pakistani forces into action in the Khyber region.
Others say the lowering of tensions with India has given the Pakistanis the space to take action in a region where the government's control has come under increased pressure and where it was already planning action.
The top administrator in Khyber, Tariq Hayat, told the BBC the operation had been started to counter a sudden spike in militant violence in Peshawar and along the Khyber Pass road that passes through the region and serves as a crucial supply line for Nato and US troops based in Afghanistan.
"Militants having bases in Jamrud have destroyed scores of containers with supplies intended for Afghanistan, and cases of kidnapping-for-ransom have shot up in recent weeks, making it imperative for the government to move to re-establish its writ," he said.
While this is largely true, analysts are generally sceptical of the ability or intention of the Pakistani security forces to gain concrete results in anti-militant operations.
The operations in the north-western regions of Swat and Bajaur have gone on for months without achieving the objective of neutralising or clearing militants from those regions.
The latest operation in Khyber is not the first in the area. For a month this summer the security forces conducted an operation against militant groups in the Bara sub-division of Khyber.
Since the operation the Khyber Pass road has never been more insecure.