SEOUL (Reuters) - North Korea found two U.S. journalists it has held since March guilty of illegal entry and sentenced them to 12 years hard labour, its official KCNA news agency said on Monday.

The journalists, Euna Lee and Laura Ling, of U.S. media outlet Current TV, were arrested while working on a story near the border between North Korea and China. Their trial opened on Thursday.

“The trial confirmed the grave crime they committed against the Korean nation and their illegal border crossing as they had already been indicted and sentenced each of them to 12 years of reform through labour,” KCNA said in a brief dispatch.

Experts say North Korean law dictated a sentence of 10 years or more of hard labour.

Analysts said the two have become bargaining chips in high-stakes negotiations with the United States, which has long sought to end the North’s nuclear ambitions.