Prime Minister Robert Fico of Slovakia was shot five times on Wednesday, in the most serious attack on a European leader in decades. Officials said the act was a politically motivated assassination attempt, stoking fears that Europe’s increasingly polarized and vitriolic politics could tip into violence.

Mr. Fico, a veteran populist politician, underwent hours of emergency surgery after being critically wounded in a town in central Slovakia. Hospital and government officials said Thursday that Mr. Fico’s condition had stabilized overnight but remained serious.

Here is what we know about the shooting.

Videos from the scene indicate that Mr. Fico was shot in Banikov Square, in the center of the town of Handlova, where the prime minister had held a government meeting.

The attacker is seen in the videos standing with other people behind a metal barrier before stepping forward and shooting Mr. Fico from just a few feet away as he came to greet them.

Mr. Fico doubled over at the waist and fell backward onto a bench, and security officers hustled him into a black car. Mr. Fico was airlifted to a hospital in Banska Bystrica, a city near Handlova, according to Slovak officials.