The Hungarian authorities appealed to the public on Friday for help in finding two migrants whom the government accused of terrorism for taking part in protests this week against the closing of the border with Serbia which degenerated into bloody clashes.

Although the violence in the street battle between the police and protesters seemed similar to confrontations at demonstrations around the world, Tamas Menczer, a Foreign Ministry spokesman, described the hurling of rocks and sticks by frustrated migrants as a serious crime.

“A person who attacks the border is committing an act of terrorism,” Mr. Menczer said, as images of the two suspects were broadcast on state television.