An American development expert kidnapped 12 days ago in Lahore has been rescued, a Pakistani police official said Thursday.

We have recovered Dr. Weinstein from the Khushab area and we are still investigating the details, a police official in Lahore told Reuters. Khushab is in Pakistan's Punjab state.

The U.S. Embassy, however, said it could not confirm the release of Warren Weinstein, 70, the country director for J.E. Austin Associates Inc., an Arlington, Va.-based consulting firm.

He had been working on a development project in Pakistan's northwestern tribal areas, where Pakistani troops have been battling Islamist insurgents for years.

Up to eight assailants kidnapped Weinstein in a pre-dawn raid on his house in Lahore Aug. 13.

The raid raised worries among aid workers, diplomats and other foreigners working in Pakistan.

Weinstein had been living in Pakistan for five to six years, according to police. He mostly lived in Islamabad but had been traveling to Lahore.

Kidnapping for ransom is relatively common in Pakistan, although foreigners are not often targets.

Militants also occasionally take foreigners hostage but these incidents have taken place in the volatile western regions bordering Afghanistan, where Islamist insurgents are very active.

Pakistani Taliban, linked to al-Qaida, have claimed responsibility for kidnapping a Swiss couple in July in the volatile southwestern province of Baluchistan.

Eight Pakistani employees of a U.S.-based aid organization, American Refugee Committee, were kidnapped in Baluchistan last month.

(Reporting by Mubashir Bukhari and Zeeshan Haider; Writing by Chris Allbritton; Editing by Rebecca Conway and Sanjeev Miglani)