Three Americans imprisoned in North Korea will return to the U.S. with Secretary of State Mike Pompeo after they are released Wednesday, according to a new report.

Pompeo, who arrived in Pyongyang Tuesday, is aiming to finalize details for the upcoming summit between President Trump and North Korean leader Kim Jong Un.

He is also working to secure the release of the three prisoners, Kim Dong Chul, Kim Sang Duk, and Kim Hak Song.

"We expect him to bring the date, time and the captives," a South Korean official said, per Yonhap News Agency .

Earlier this year, Trump announced he would meet Kim with the goal of denuclearizing the Korean Peninsula. Trump said on Tuesday he was optimistic a deal for future “prosperity” and “security” with North Korea could be reached.

“Plans are being made. Relationships are building,” Trump said. “Hopefully, a deal will happen and, with the help of China, South Korea, and Japan, a future of great prosperity and security can be achieved for everyone.”

The South Korean official's comments follow South Korean President Moon Jae-in's historic summit with Kim last month, which resulted in an agreement to sign a peace treaty and a stated dedication to denuclearization.