Wednesday's sudden visit comes after Putin spoke by phone with Hungarian Prime Minister Viktor Orbán on Tuesday, the AFP news agency reported.
According to the news site EU Observer, Putin thanked Hungary for its "principled" and "independent" policy regarding Ukraine during the conversation.
Hungary is currently blocking a fresh multi-billion-euro loan from the EU to Ukraine and also the latest sanctions package against Russia. The reason is that Ukraine has stopped oil shipments from Russia to Hungary, citing damage to the pipeline by Russian attacks.
The blockage also comes as the election campaign in Hungary is heating up ahead of the parliamentary elections on April 12, when Orbán and his government are challenged by leading opposition candidate Péter Magyar.
