More campaigns similar to the anti-migration billboard seen in Brussels, commissioned by Hungary's government, could be organised if the country's leaders are “rejected” by the European Parliament, Budapest's secretary of state for international communications told Euronews.

Zoltán Kovács said the billboard was commissioned in response to what he called the European Commission's “pro-migration agenda,” a policy that he claims most Europeans are against and poses a security risk to the region.

“We won't let it go if the Hungarian government is rejected,” he said.

The mobile billboard appeared on the streets of Brussels on Thursday with an image of Guy Verhofstadt — MEP, leader of the liberal ALDE group in the European Parliament and a fierce critic of Hungarian Prime Minister Viktor Orbán.

Kovács added the image of Verhofstadt was chosen as he is a “leading figure of pro-migration in the European parliament.”

The billboard said: "Hundreds have died in terrorist attacks since 2015 but Guy Verhofstadt says: 'We don't have a migration crisis.' This is insane!"

Brussels police stopped the van carrying the billboard, a police spokesperson told Euronews, to draw up a case against the driver but did not disclose on what grounds.

“They put out a van for a migration campaign and we did the same,” Kovács said as he accused Brussels of “double standards”.

Verhofstadt posted a message on his Twitter in response accusing Hungary of copying a similar campaign he ran earlier, but one that prompted migration and freedom of movement in Europe.

Verhofstadt, former Prime Minister of Belgium, said in October that the European Parliament should "cut Orbán loose and send him where he belongs; the dunghill of politics."

The police intervention prompted a response from Hungary, which accused Brussels of censorship.

Orbán has made anti-immigration policy his signature issue and his government has led eastern-European opposition to European Union quotas to distribute migrants around the bloc.

Orban followed the billboard incident closely and the Hungarian government is waiting for a formal explanation from Brussels, Kovács said.

Euronews contacted Guy Verhofstadt’s office for comment but it had not responded at the time of publication.