European Commission President Jean-Claude Juncker jokingly called Hungary's leader a "dictator" upon his arrival for a European Union summit.

The gibe targeting Prime Minister Viktor Orban was picked up by TV cameras covering Friday's official welcome at the Riga summit.

When Orban approached, Juncker said "the dictator is coming," prompting a nervous laugh from Latvian Prime Minister Laimdota Straujuma.

Juncker then greeted Orban with the word "dictator" and slapped him on the right cheek.

Orban took it in stride, greeting Straujuma before telling Juncker to "behave, please" as they lined up for photos.

Some have labeled Orban a dictator for his weakening of democratic checks and balances, crackdown on civic groups and efforts to build an "illiberal state" taking cues from authoritarian regimes like Russia and China.