North Korea remained silent Friday on the fate of two female American journalists who are being tried on charges that could send them to a labor camp for years.

On Thursday, North Korean state media announced that Euna Lee and Laura Ling of U.S. media company Current TV were scheduled to go on trial at 3 p.m. local time (0600 GMT). Pyongyang has yet to comment further on the trial.

The U.S. State Department says North Korea has barred observers from attending the trial.

North Korean authorities arrested Lee and Ling in March while they were working on a story near the Chinese-North Korean border.

Pyongyang charged the journalists with hostile acts and illegally entering the country. If convicted, they could face a sentence of up to 10 years in a labor camp.

Late Wednesday, before the trial began, relatives and supporters of Lee and Ling held candlelight vigils in several U.S. cities and pleaded for leniency.

Since their arrest, political analysts have speculated that North Korea may use the pair as a diplomatic bargaining chip in disputes with the United States.

The Obama administration has dismissed the charges against the reporters as "baseless" and urged Pyongyang to release them.

The U.S. State Department is not ruling out the possibility of former Vice President Al Gore traveling to North Korea to personally negotiate for the women's release.  Gore is the founder and chairman of Current TV.

But spokesman Ian Kelly told reporters Thursday he could not go into details about Gore's possible involvement, calling it a "very, very sensitive issue."

Some information for this report was provided by AFP.