"This prisoner exchange is a major development. We hope to see more Ukrainian prisoners reunited with their families in the future," he wrote.
Bolton has also written that the U.S. continues to stand with the people of Ukraine.
He also added a post of U.S. President Donald Trump where he congratulated the both countries on the exchange of prisoners and called it "first giant step to peace".
Ukraine and Russia exchanged detainees in the 35-for-35 format on September 7. The list included eleven Ukrainian political prisoners illegally convicted in Russia and 24 Ukrainian sailors who were captured near the Kerch Strait in late November 2018.