Ukraine marked the 16th anniversary of its independence from the Soviet Union. Honor guards marched across a main Kiev square, bells tolled and religious leaders led prayers for the country.
President Viktor Yushchenko called for unity ahead of next month's parliamentary elections, which come as the country faces continuing political turmoil and sparring among major parties.
"Tens and hundreds of years will pass but this day will always be a triumph of our freedom," Yushchenko said in his speech, as several hundred people - some clad in traditional peasant-style shirts and skirts - waved blue-and-yellow flags in front of Kiev's landmark St. Sofia Cathedral.
Yushchenko also signaled he would seek to push new constitutional amendments on the distribution of political power.
Constitutional changes that went into effect last year watered down presidential powers in favor of the prime minister and Yushchenko has sought to reverse that.
Ukrainian lawmakers declared independence on Aug. 24, 1991, days after the hard-line Communist coup against Soviet President Mikhail Gorbachev failed.
More than 90 percent of Ukrainians approved the decision in a referendum that December, when the Soviet Union officially ceased to exist.
It is assumed that the fighter will be created using new stealth technologies and have a very large interception range - up to 1,500 kilometers