Updated

An international media rights group renewed a call Friday for the release of two American reporters held in North Korea for the past month.

Laura Ling and Euna Lee, journalists working for former Vice President Al Gore's San Francisco-based Current TV, were arrested after they allegedly crossed the border from China on March 17 while reporting on North Korean refugees.

The North has said it will put them on trial for the alleged border incursion and unspecified "hostile acts."

If convicted of espionage, the women could face at least five years in prison under North Korean law.

On Friday, Paris-based Reporters Without Borders called for their immediate release in a statement, condemning Pyongyang for treating the reporters as "criminals" when they were "simply doing their jobs."

Their prolonged detention comes amid tensions on the Korean peninsula after the North this month fired a rocket, vowed to restart its nuclear program, said it will quit six-nation disarmament talks and kicked out international nuclear monitors.

The North is angry that the U.N. Security Council criticized what Pyongyang calls a "peaceful" satellite launch. Other nations believe the liftoff was a test of its long-range missile technology.

Separately, the North has also been holding a South Korean worker from an inter-Korean industrial complex since March 30 for allegedly denouncing Pyongyang's political system.

Many analysts have said the North is likely to try to use the U.S. and South Korean citizens as bargaining chips for future talks with Washington and Seoul.