Ukraine's armed forces claim to have killed "around 100" rebel fighters near the eastern town of Snizhne.
Defence officials said government forces had also destroyed 11 missile systems and tanks but the claims could not be immediately verified.
While rebels said they had seized two settlements west of Snizhne and captured 13 Ukrainian troops, including three officers.
More top news
Gordon Brown has said forced child migration schemes that continued until the 1970s amounted to "government-induced trafficking".
200 UK officers already working on the case are sifting through 15 tonnes of debris on each of the building's 24 floors.
Levels of crime - including violent offences - saw their most dramatic rise in a decade last year, new figures show.