At least three people were killed during a security operation in northwestern Pakistan on Monday, the Pakistan Army said.

The fatalities included a colonel and two suspected militants, according to a statement from the army's media wing.

Security forces conducted a counter-terror operation in Tank district that borders the restive South Waziristan region acting on an intelligence tip off.

"As soon as troops cordoned off the area, the terrorists opened fire," the statement said, adding that a large cache of arms and ammunition was recovered from the terrorist hideout .

It did not reveal the affiliations of the slain militants.

But the latest operation is part of an ongoing crackdown against the Pakistani Taliban, which Islamabad claims has set up bases across Afghanistan's border to attack Pakistani forces.

More than 5,000 suspected militants and over 700 soldiers have been killed in airstrikes, clashes and landmine blasts over the past six years, according to officials.

The figures, however, could not be independently verified as media access to the tribal area is restricted.