As the United Nations prepares to leave its New York headquarters for a four-year renovation, staff are scouring the corridors to try to find valuable works of art that have gone missing.

The lost items include a sculpture by Jose de Rivera, the 20th century American abstract expressionist, and an oil painting entitled "Evening", a gift from Belarus. An internal audit said the absence of these art works, listed as gifts in the UN's files, was of "extreme concern".