South Korea — North Korea on Monday sentenced two American journalists to 12 years of hard labor in a case widely seen as a test of how far the isolated Communist state was willing to take its confrontation with the United States.

The Central Court, the North’s highest court, held the trial of the two Americans, Laura Ling and Euna Lee, from Thursday to Monday and convicted them of “committing hostilities against the Korean nation and illegal entry,” the North’s official news agency, KCNA, said in a report monitored in Seoul.

Ms. Ling and Ms. Lee were on a reporting assignment from Current TV, a San Francisco-based media company co-founded by Al Gore, the former vice president, when they were detained by the soldiers. The reporters were working on a report about North Korean refugees — women and children — who had fled their homeland in hopes of finding food in China.

The circumstances surrounding their capture remain unclear.