KIEV, Ukraine — The protracted struggle for Ukraine between Russia and the West was on vivid display on Monday with Russia throwing an unexpected financial lifeline to the embattled Ukrainian president, Viktor F. Yanukovych, just as Germany rolled out an unusually high-level reception for two of the president’s most ardent opponents.

As the Ukrainian opposition leaders, Arseniy P. Yatsenyuk and the former boxing champion Vitali Klitschko, huddled in Berlin with German leaders, including Chancellor Angela Merkel, Russia said it would this week unblock the next payment of a promised $15 billion credit for Ukraine that it had earlier frozen because of the political disarray in the Ukrainian capital, Kiev.

Russia’s decision to resume financial support for Ukraine gives a needed lift to Mr. Yanukovych ahead of a parliamentary session on Tuesday at which the opposition is expected to push for constitutional changes to trim the president’s powers. It also does an end run around Europe’s sluggish efforts to support the opposition by coming up with an aid package of its own.

The European Union and the United States have repeatedly said they are “working on” financial assistance for Ukraine in conjunction with the International Monetary Fund, but so far no offers have been made public. While insisting that they do not want to get into a bidding war with Russia for Ukraine’s allegiances, European leaders have come under pressure from prominent pro-European Ukrainians to provide concrete help, not merely high-minded declarations about the transformative power of European values.