An international media rights group urged North Korea to drop plans to put two detained U.S. reporters on trial, saying they face up to 10 years of forced labor in a prison camp if convicted. Reporters Sans Frontieres (RSF, Reporters Without Borders) also said it was “by no means clear” that the two women from California were on North Korean territory when they were detained by the North’s border guards on March 17, the Associated Press reports.

The Paris-based group said it was the first time foreign journalists have been held in the North for any length of time since the detention of Japanese reporter Takashi Sugishima from December 1999 to February 2002.

In Washington, the State Department said Tuesday it is still working with Sweden, which represents U.S. interests in Pyongyang, in a bid to win their release.