Republican Sen. Kelly Ayotte is asking Defense Secretary Ash Carter to take every reasonable step to make sure that the five Taliban leaders released from Guantanamo Bay in exchange for Sgt. Bowe Bergdahl are not allowed to return to the battlefield in Afghanistan.

Ayotte said in a letter she sent Carter on Wednesday that the one-year travel ban the Taliban figures faced when they were released and sent to Qatar will expire June 1.

She says no American should ever have to confront a former Guantanamo detainee on the battlefield.

She also reiterates her opposition to the swap, which the Obama administration conducted without notifying Congress.

Bergdahl was held by the Tailban for five years. The U.S. military charged him Wednesday with desertion and misbehavior before the enemy.