KIEV, Feb. 22 - A bid by regional leaders loyal to President Viktor Yanukovych to challenge the legitimacy of the national parliament appeared to founder on Saturday, after thousands of protesters rallied in eastern Ukraine in support of the political changes in Kiev.

The meeting of governors of mainly Russian-speaking regions in the northeastern city of Kharkiv had raised the possibility of a split in the vast former Soviet republic of 46 million. The leaders denied that this was their intention.