A new U.S. congressional report says the United States cannot ensure that former detainees at the Guantanamo Bay military prison will not become involved in insurgent activities.

The report by the oversight panel of the Republican-led House Armed Services Committee says 27 percent of the 600 detainees transferred out of Guantanamo were confirmed or suspected to be presently or previously engaged in terrorist activities.

The report comes as the Obama administration is considering transferring some Taliban inmates from the prison to Qatar, in an effort to engage the Taliban in peace talks.