Bulgaria’s Prime Minister Boiko Borisov has said he will resign as promised after his centre-right party’s candidate lost the race to become the Balkan country’s next president.

Exit polls on Sunday suggested a large victory for Socialist Party ally Rumen Radev, a newcomer to politics seen as friendly to Russia.

Borisov told reporters: “On the first working day of the parliament we will tender the government’s resignation.”

The collapse of Borisov’s minority government is likely to result in months of political uncertainty, probably triggering early elections in the spring.

The polls suggested that Radev won around 58 percent of the vote compared to around 35 percent for Tsetska Tsacheva, the candidate of the ruling centre-right GERB party.

Radev, a former air force commander, campaigned on strong anti-migrant rhetoric and an argument that Bulgaria should try to balance the demands of European Union membership and better ties with Russia.