UPDATE 1-Bush to visit Ukraine before NATO talks -Yushchenko

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BRUSSELS, March 13 (Reuters) - U.S. President George W. Bush will visit Ukraine at the end of this month, Ukrainian President Viktor Yushchenko said on Thursday, a visit timed just days before a NATO decision on ties with the ex-Soviet state.

"I can now officially state that President Bush will make an official visit to Ukraine from March 31 to April 1," Yushchenko told reporters during a trip to Brussels.

NATO allies are due to decide at an April 2-4 NATO summit in Bucharest whether to meet Ukraine's request for a framework setting out steps towards possible membership of the alliance.

Russia is deeply opposed to Kiev's membership aspirations and several west European countries have reservations about advancing rapidly with Ukraine.

"There is still a lot of work to be done about negotiations with different countries ... I am very optimistic about it," said Yushchenko, in Brussels for talks with EU officials.

"We are not speaking about joining NATO today ... There were cases of countries that were three, five, eight years in the MAP," he said of NATO's Membership Action Plan (MAP), the framework which sets out the reforms needed for NATO membership.

Yushchenko stressed that any final decision on membership would be taken by referendum in his country, where polls show strong public opposition to such a move.

NATO allies are also set to discuss a similar request by Georgia at the Bucharest meeting.