Ukraine's President Viktor Yushchenko says he will again veto a bill that would weaken presidential powers.
President Yushchenko said Thursday he will not sign the proposed law, which he says violates the constitution.
Last week, the Western-leaning president vetoed the bill which would deprive the president of the right to veto parliament's choice of prime minister and of the right to name the foreign and defense ministers.
The parliament overrode his veto on Friday.
Under Ukraine's constitution, after an override, the president is obliged to sign the bill into law. But the president's office says it found a change in the version submitted for Mr. Yushchenko's signature, allowing him to again veto the bill.
Ukraine's Foreign Ministry has been a focus of dispute between the president and Prime Minister Viktor Yanukovych since lawmakers voted to dismiss Borys Tarasyuk in early December.
Mr. Yushchenko reappointed him but supporters of Mr. Yanukovych blocked Tarasyuk from entering cabinet meetings.
The Western-leaning president won the 2004 election in a second poll after a bitter contest with Mr. Yanukovych, who supports closer ties with Russia. In a later political compromise, the president appointed Mr. Yanukovych prime minister to break a political stalemate that had gripped Ukraine since elections in late March.
Some information for this report was provided by AP.