KIEV (Reuters) - President Viktor Yanukovich and the opposition are expected to sign an agreement brokered by the European Union on Friday to resolve Ukraine's crisis although the opposition still wants some changes, a senior EU diplomat said.

The envoy gave no details except to say that the deal would set out plans for constitutional reforms to be carried out by September. The reforms are widely expected to entail reducing the president's powers.

(Reporting by Sabine Siebold, Editing by Timothy Heritage)