A group of American activists is in Pakistan, planning to join a march into the country's tribal belt to protest U.S. drone strikes.

There have been concerns that Islamist militants will target Saturday's event.

The main Pakistani Taliban faction already has issued a statement criticizing the march, which is to be led by Imran Khan, the former cricket star-turned-politician.

Around three dozen representatives of the U.S.-based activist group CODEPINK want to march alongside Khan. They met Friday in Islamabad with alleged victims of drone strikes.

Opponents argue the strikes kill large numbers of innocent civilians and terrorize the tribes living in Pakistan along the Afghan border.

The U.S. rarely discusses the top-secret drone program, but American officials have said the majority of those killed are al-Qaida and other militants.