"As everybody is aware, the past Administration has long been asking for three hostages to be released from a North Korean Labor camp, but to no avail. Stay tuned!" the president tweeted.
Media reported earlier this week that three Korean-Americans had been freed from labor camps in North Korea and were receiving treatment near Pyongyang.
Their release would demonstrate North Korea's "goodwill" ahead of Trump's planned summit with Kim Jong-un in the coming weeks, according to US national security adviser John Bolton.