Bosko Obradovic, the leader of Serbia's nationalist opposition Dveri movement, called on Tuesday on Serbia's military and police to take over the country to protect it from migrants, the Beta news agency reported.
He said it was necessary, accusing President Aleksandar Vucic of "keeping borders open to get (German Chancellor) Angela Merkel's (George) Soros' support to remain in power."
"Right now, Vucic is the most dangerous security threat to Serbia and has to be immediately isolated. So, the army and police should take power and protect the state borders from the upcoming migrants' crisis. If they don't do that, I don't know who will," Obradovic told reporters in the Parliament's hall.
He said that migrants who were coming to Serbia were not families running away from wars and who "absolutely should be helped," but "men of military age, 18 to 30 years old, without IDs, people without identity who are a severe threat to Serbia."
"What are they hiding; do our security service security check them; what wars they have taken part in," Obradovic asked.
He added that all countries on the so-called Balkan migrants' route were closing their borders, but that Vucic did not want to do that in Serbia, but made it borders "the most open to illegal entry."
"We should follow the footsteps of the Visegrad Group countries which strictly control state borders and prevent an illegal crossing of illegal migrants," Obradovic said.
The first Government reaction came from Defence Minister Aleksandar Vulin who said that "the Army of Serbia firmly stands by its Commander-in-Chief Aleksandar Vucic and protects the Constitutional order."
Soon after, high-ranking officials of Vucic's ruling Serbian Progressive Party (SNS) joined Vulin in describing Obradovic's statement as the call for coup d'etat.
Zorana Mihajlovic, Serbia's Government Deputy Prime Minister and an SNS vice president said that "the call for coup d'etat won't have an effect and that it only shows that some politicians are willing to sacrifice the state only to come to power."
She also asked other opposition parties' leaders to say if they share Obradovic's opinion.
Her party colleague Aleksandar Markovic said Obradovic "spreads fear and panic and call for a coup d'etat."
"Bosko Obradovic makes Serbia's enemies happy again by calling for civil war among Serbs and the violent overthrow of the authorities," Vulin said.
He recalled that Obradovic "in 2105 lied that 400,000 migrants came to Serbia, and he's lying again."
Vulin added that Vucic "protected Serbia in 2015 at the peak of the migrant crisis and that he will do that now as well."
"Obradovic must immediately be held responsible for calling for an armed mutiny. Either the Prosecutor's Office or psychiatrists should take care of him," Vulin said.