Ukraine's leaders trade threats

By Elizabeth Piper

KIEV (Reuters) - A power struggle between Ukraine's president and prime minister deepened on Thursday with both men refusing to back down over a new election and threatening each other with prosecution.

President Viktor Yushchenko has issued a decree to dissolve parliament and stage an election in what is regarded as a final bid to reassert his authority. Prime Minister Viktor Yanukovich has refused to take part in the poll.

The pro-Western president's popularity has slid after accusations he betrayed the promise of the "Orange Revolution" 2-1/2 years ago to take ex-Soviet Ukraine closer to the West and eventually join the European Union.

He accuses Yanukovich, whom he swept aside in that upheaval, of violating the constitution by poaching members of his team to enlarge the majority in parliament underpinning the government.

Thousands of the prime minister's supporters, many brought by bus from his power base in eastern Ukraine, have taken to the streets, calling for Yushchenko to step down.

Unlike in 2004, gatherings in Kiev's Independence Square were relatively small and low-key.

"I stress one more time that it is obligatory to implement the decree of Ukraine's president. Any refusal to implement it will result in criminal proceedings," Yushchenko told a meeting of Ukraine's Security Council, where he sat next to Yanukovich.

"I will not take a single step towards rescinding the decree."