A live television weather report from northern Serbia was interrupted on Friday by a man who waved what appeared to be a handgun in front of the camera.
Police said they were trying to identify the man and whether the gun was real.
The incident happened during a weather report on Radio-Television Vojvodina, the public broadcaster of Serbia’s northern Vojvodina province, early in the morning.
The province’s Independent Association of Journalists suggested the incident resulted from a climate of xenophobia, nationalism and intolerance of criticism in Serbia, and accused authorities of sending daily “messages of hate”.
The province of Vojvodina is controlled by the Democratic Party, which is in opposition at the national level to the ruling Progressive Party. The government has made clear it views coverage by Radio-Television Vojvodina as biased against it.
Journalists in Serbia have frequently been the targets of intimidation or worse since the rule of the late strongman Slobodan Milosevic, when Yugoslavia collapsed in war.
In the incident, a hand holding what appeared to be a small revolver appeared briefly in front of the camera as a woman presented a weather report from an outdoor market in the main Vojvodina city of Novi Sad. Neither the presenter nor the studio anchor remarked on the incident at the time, but the broadcaster later reported it to police.
"The case is being investigated, including the identity of the perpetrator and whether the handgun was fake or real," said interior minister Nebojsa Stefanovic.
“This is intolerable and we will try to determine the identity of that person as soon as possible,” he said.