Al-Qaida says it is holding an American aid worker kidnapped last August from his home in Pakistan, and will not release him unless the United States halts its airstrikes in Muslim countries.

The U.S.-based SITE Intelligence group, which monitors jihad websites, said Thursday al-Qaida chief Ayman al-Zawahiri made the claim in a video statement. The monitoring group says al-Zawahiri is also demanding the release a number of al-Qaida and Taliban prisoners.

Al-Zawahiri says al-Qaida kidnapped Warren Weinstein, who, he said, is “neck-deep in American aid to Pakistan” just like the U.S. detains anyone they suspect “even remotely” of links to al-Qaida and the Taliban.

The 70-year-old Weinstein was snatched from his home on August 13 after eight gunmen overpowered his security guards.

Weinstein served as director in Pakistan of a U.S.-based development consulting company, J.E. Austin Associates. The president of the company has issued an appeal for his release, saying friends and family are concerned about his health.