BERLIN, Dec 29 (Reuters) - The foreign ministers of Germany, France, Britain and the United States discussed the situation at the Ukrainian border and upcoming dialogue formats with Russia, Germany"s foreign ministry said on Twitter on Wednesday. The four foreign ministers also discussed the latest round of international talks in Vienna about Iran"s nuclear program and how to show solidarity with Lithuania regarding China"s recent actions, the foreign ministry said. U.S. President Joe Biden and Russian President Vladimir Putin plan to speak on Thursday as Washington crafts a common response with European allies to Russia"s military build-up on the Ukraine border. read more