Washington: The US has said it does not anticipate its military strength in Pakistan to be reduced to "zero".

"There is no anticipation that it (US forces in Pakistan) will go to zero. They (Pakistan) had asked us about reducing our footprint and there are ongoing discussions about what those numbers are," Pentagon spokesman Col Dave Lapan told reporters during an off-camera briefing on Wednesday.

"These are really short of ongoing discussion that we have with them. It's not that finite," he said, adding the number of US personnel depends on the type of operation and cooperation America was having with Pakistan.

Currently, there are between 200 to 300 US military personnel in Pakistan -- all assigned to the Office of the Defense Representative - Pakistan (ODR-P). "Those numbers fluctuate many a time, anyway but it remains within the 200 to 300 range," he said.

Lapan said it was up to Pakistan to take action against extremists in the North West Frontier Province.