The United Nations is warning that Eastern European countries along the Danube could face flooding as the iced-over waterway thaws following a record-breaking cold snap.

The warning Tuesday came from Margareta Wahlstroem, the U.N. secretary general's special representative for disaster risk reduction.

Wahlstroem says in a statement from Geneva that there are warning signs that "destructive floods will add to the loss of life and economic assets," especially in places where there are few dams and dikes.

Serbia, Bulgaria and Romania lie on the 1,777 mile-long (2,860-kilometer-long) Danube. Stretches of the river were recently blocked by thick ice as the region faced a deep freeze that claimed more than 600 lives. The ice is thawing and shifting this week as temperatures rise.