Two United States journalists are reported to have gone on trial in North Korea, on charges of committing "hostile acts".
Euna Lee, a Korean-American, and Laura Ling, a Chinese-American, were arrested on 17 March this year after allegedly crossing into North Korea from China.
The US has dismissed the charges as "baseless" and said the women should be released immediately.
The trial comes amid growing tensions in the region following North Korea's recent nuclear and missile tests.
In a new sign of friction, a North Korean patrol boat is reported to have briefly entered South Korean waters.
The South's Yonhap news agency said the vessel crossed the disputed maritime border on Thursday, but retreated when issued with a verbal warning.
Ms Lee and Ms Ling were arrested by North Korean guards while working on the China-North Korea border on a story about refugees for California-based internet broadcaster Current TV.
Some reports have suggested that the women were arrested while on Chinese soil, but Pyongyang's state media says they had illegally entered North Korea.
North Korea said the trial would begin at 3pm local time on Thursday.
If the women are found guilty, analysts say they face at least five years' detention with hard labour in a North Korean prison camp.
The women's families have appealed for clemency and asked North Korea and the US not to link the case to the current diplomatic standoff between them.
