United Nations, Jan 17 (IANS): UN Secretary-General Ban Ki-moon has welcomed the prisoner swap between the US and Iran, the UN chief's spokesman said in a statement.

Iran freed four American prisoners on Saturday, including Washington Post correspondent Jason Rezaian. US officials also confirmed that on Saturday they released four Iranian-Americans as part of the prisoner swap.

The secretary-general commended the recent moves by the governments of the United States of America and the Islamic Republic of Iran to improve ties, Xinhua reported on Sunday about the Saturday's statement.

"He is also heartened by the lifting of sanctions on Iran," the statement added.

The UN chief also expressed the hope that the parties move on to fully implement the Joint Comprehensive Plan of Action in good faith and to increase cooperation on other pressing international and regional matters, it said.

The UN chief affirmed the need for all concerned in the region to make the world a safer place through dialogue and peaceful means, it added.