An accused pedophile childcare worker has been identified as a former student of an elite Sydney school, as fresh details emerge about his past.

U.S. President Donald Trump on Thursday sharply criticized Russia's "disgusting" behavior against Ukraine and said he plans to impose sanctions on Moscow if no agreement can be reached.

Edward Zakrzewski, 60, pleaded guilty to the June 1994 murders of his wife Sylvia, son Edward, 7, and daughter Anna, 5.