Foreign Ministry spokeswoman Tasnim Aslam said no exact date had been fixed for the withdrawal of NATO troops, but Pakistan was not seeking any extension of their stay.

"Yes, we are sticking to our plans (for withdrawal)," she said.

NATO's ambassador to Pakistan Carsten Fauboll met Pakistani Foreign Secretary Riaz Mohammad Khan and discussed plans for the withdrawal of NATO's troops.

"The foreign secretary assured that the government of Pakistan would extend all cooperation to facilitate the NATO preparations to carry out withdrawal in accordance with the stipulated period," the foreign ministry said in a statement.

While plans are already being drawn up for the withdrawal, expected to begin sometime in late January, the NATO contingent was due to expand further on Friday with the arrival of Italian engineers, bringing heavy equipment, NATO sources said.

Islamist opposition politicians have been trying to stir controversy about the troops, saying NATO was seeking to establish a long-term presence, and its forces were only interested in hunting Osama bin Laden and his al Qaeda cohorts.

A NATO air-bridge from Germany and Turkey to Pakistan has been a crucial factor in delivering food and shelter. NATO engineers are clearing roads, while medics have established field hospitals in stricken areas.