BRUSSELS — Former European leaders who tried to bring Ukraine closer to Europe before a 2014 uprising there reacted with shock on Saturday after a federal indictment accused Paul Manafort, President Trump’s former campaign chairman, of secretly paying former European officials some two million euros in 2012 and 2013 to lobby on the country’s behalf.

Ukraine at the time was led by Viktor F. Yanukovych, who first agreed to closer ties to Europe and then reneged under Russian pressure and was toppled in the uprising.

The indictment, released on Friday by Robert S. Mueller III, the special counsel investigating Russian interference in the 2016 election in the United States, did not name the former officials, but it set off furious speculation about who they might be.

The indictment says the lobbying effort was managed by a former chancellor of a European country, identified as “Foreign Politician A,” in coordination with Mr. Manafort.