Two U.S. journalists who were detained in North Korea while covering the plight of defectors living along the China-North Korea border have been sentenced to 12 years in labor prisons, the country's state-run media said Monday. Euna Lee has been in North Korean custody since March when she and another reporter were detained. The Central Court of North Korea sentenced Laura Ling and Euna Lee for the "grave crime they committed against the Korean nation and their illegal border crossing," the Korean Central News Agency said. As a result, the court sentenced the women to "12 years of reform through labor," meaning they will serve out their sentence in a labor prison. CNN quoted the U.S. State Department as saying that it had seen the reports of the convictions and was trying to confirm it with Korean authorities. "We are deeply concerned by the reported sentencing of the two American citizen journalists by North Korean authorities, and we are engaged through all possible channels to secure their release," said spokesman Ian Kelley in a statement. "We once again urge North Korea to grant the immediate release of the two American citizen journalists on humanitarian grounds." Ling and Lee were taken into custody March 17. They are reporters for California-based Current TV.