The United States is calling for North Korea to grant amnesty to two reporters sentenced last month to 12 years of hard labor for illegally entering the North.

State Department spokesman Ian Kelly's call for amnesty Thursday for Euna Lee and Laura Ling marks a shift from past U.S. calls for their release on humanitarian grounds.

Ling's sister told a U.S. TV station that Laura acknowledged breaking North Korean law during a recent phone call and that she and Lee need the U.S. government's help in obtaining amnesty.

The women were working for U.S.-based Current TV. The North says they documented their journey into North Korea, even pocketing a stone to commemorate the illicit trip across the frozen Tumen River from China.