KIEV, Sept. 14 - Boris Berezovsky, an exiled Russian billionaire living in Britain, on Wednesday attacked President Viktor Yushchenko by suggesting that he may have contributed $15 million to finance Yushchenko's presidential campaign last year.

The attack comes at a sensitive time as Yushchenko tries to assemble a new government coalition that may include moderate opposition parties after dismissal of Prime Minister Yulia Tymoshenko Sept. 8.