Slovakia's President Andrej Kiska speaks at the party headquarters of Slovakia's presidential candidate Zuzana Caputova in Bratislava, Slovakia, March 30, 2019. REUTERS/Radovan Stoklasa

BRATISLAVA (Reuters) - Slovakia’s outgoing president said on Wednesday he would form a new political party when his term expires in June, aiming to unite the country’s liberal, pro-European Union camps.

Andrej Kiska had not run for re-election but endorsed the eventual winner, Zuzana Caputova. A civic campaigner and anti-graft lawyer, her landslide victory last weekend encouraged the pro-EU liberals Kiska hopes to lead.

“Slovakia wants change. We won this election, now we have to win the general election,” Kiska said in a video posted on his official Facebook page. “I will start a political party, and I want to unite all decent and willing people and change our country for the better.”

The Slovakian presidency is largely ceremonial, but Kiska made it an influential office. He sided with protesters who mounted massive demonstrations after the killing last year of Jan Kuciak, a reporter covering corruption, and his fiancee, Martina Kusnirova.

The protests led to the resignation of Robert Fico as prime minister. Fico’s ruling party, Smer, saw its support plunge after Kuciak’s and Kusnirova’s murders.

Political analysts said it was not clear whether Kiska, the country’s most trusted politician, with an approval rating of 57 percent, can unify the disparate opposition or will further fragment the centrist pro-EU, anti-graft camp.

An AKO agency poll of 1,000 people last month showed 9 percent of voters would certainly and 31 percent would probably vote for his party if he set one up.

Its natural allies, Caputova’s Progressive Slovakia, which runs on a joint slate with Spolu (Together) party, saw their joint support double since February to 14.4 percent. Caputova will quit her party in the coming days in a nod to a tradition that the president is non-partisan.

The leftist but socially conservative Smer saw its support fall under 20 percent for the first time in more than a decade. Support for anti-European, far-right People’s Party-Our Slovakia rose to 11.5 percent in April from 9.5 percent in February.