SOFIA, Bulgaria (AP) — The center-right GERB party of former Prime Minister Boiko Borisov took the lead in Bulgaria's parliamentary election on Sunday, a pair of exit polls showed, a result that if confirmed by official returns indicates support for the country keeping its European identity.

The Alpha Research exit poll said GERB won 32.2 percent of the vote, with the Socialist Party coming in second with 28 percent, while a separate exit poll by Gallup International Balkan had GERB with 32.8 percent and the Socialists with 28.4 percent.

Official results are expected Monday. If they confirm the exit polls, Borisov, a political maverick who combines man-in-the-street rhetoric with a pro-European Union disposition, will be handed a mandate to form his third cabinet.

GERB did not win enough votes to govern alone, and will likely form a coalition government with the United Patriots, an alliance of three nationalist parties that the exit polls showed placing third.

Borisov, 57, resigned as prime minister after his party lost the November 2016 presidential election. Parliament was dissolved in January, and the president appointed a caretaker government that will stay until a new government is formed.

Borisov said GERB had the "duty to form a government because this is the will of the people and because we triggered these early elections." He declined to say what parties may be in a future coalition, pending final results.

Support for the nationalist alliance reflected widespread anger over an influx of migrants to this southeastern European nation that borders Greece, Turkey and Romania, and over Turkey's open support for a party representing Bulgaria's sizeable Muslim minority.

Along with the immigration, the election campaign focused on the future of the European Union, which Bulgaria joined in 2007, and the influence of Russia and Turkey on domestic politics.

The Socialist Party of ex-communists has pledged to improve economic relations with Russia, appealing to voters who feel let down by the EU. Bulgaria is also a member of NATO.

Socialist leader Kornelia Ninova wants EU sanctions against Russia lifted, seeks a bigger role for the state in the economy and has wooed voters with promises of higher salaries and pensions.

Ninova said she voted Sunday "for security at our borders and inside the country, for justice, and lastly not to give an opportunity to another country, no matter if it comes from East, West or South, to interfere in our politics," she said Sunday.

The GERB party's popularity faded because of the slow pace of reforms to eliminate graft and poverty and overhaul the judicial system. It is now pledging to fight corruption and to raise minimum wages, and supports EU sanctions on Russia over its role in the Ukraine crisis.

A populist party named Volya (Will) may end up entering Parliament. Exit polls showed it winning about 5 percent of the vote, exceeding the 4 percent minimum threshold.

The party is led by Veselin Mareshki, a wealthy businessman whose anti-establishment message combines patriotic rhetoric with promises of strict immigration controls and friendlier relations with Moscow.

The Central Election Commission said voter turnout for the election stood at nearly 43 percent at 5 p.m., a larger showing than in previous elections.

The election sparked protests at the Turkish border by Bulgarian nationalists who were determined to keep Bulgarian citizens living permanently in Turkey from coming in to vote. The protesters claimed Turkish officials were forcing expatriate voters to support DOST, a pro-Ankara party running for the first time.

Some 10 percent of Bulgarians are of Turkish origin or Muslim. More than 300,000 Bulgarians have settled permanently in Turkey, but still hold Bulgarian passports and are eligible to vote.

The border tensions prompted a spat between the two nations' leaders. While Turkish President Recep Tayyip Erdogan has criticized what he described as "pressure" on ethnic Turks in Bulgaria, Radev retorted that his country would not accept democracy lessons from Turkey.

"We will not allow any interference of foreign powers in Bulgaria's internal affairs," Borisov said Sunday.