Polish president Lech Kaczynski was hospitalized with an acute viral infection, but was apparently not in any serious danger and would be released later in the day, his doctor said.
Kaczynski was taken to an army hospital in Warsaw early Monday after suffering a high fever in the night and general weakness, his doctor, Wojciech Lubinski, said at a news conference broadcast live by the all-news station TVN24.
Lubinski said that Kaczynski's condition was already improving.
Poland has seen months of political uncertainty that is expected to result in early elections this autumn, two years ahead of schedule. Parliament is scheduled to vote Friday on whether to dissolve itself, which would trigger the early election.
Should that motion not pass, Prime Minister Jaroslaw Kaczynski, the president's twin brother, has said he will resign, which would also lead to an early election, though by a more complicated process.
Russian President Vladimir Putin and German Chancellor Angela Merkel had had a few fights and used strong language because of the Ukrainian crisis in 2014