BUDAPEST (Reuters) - Slovakia’s new president called on the Visegrad group of eastern EU member states on Thursday to protect the rule of law to avoid being seen as “weakening the European Union”, signaling a possible rift within a bloc that often acts together.

FILE PHOTO: Slovakia's President Zuzana Caputova pays her respects at the grave of former Czech President Vaclav Havel at Vinohrady Cemetery in Prague, Czech Republic, June 20, 2019. REUTERS/Bundas Engler

After meeting with Hungarian President Janos Ader, Slovak President Zuzana Caputova said cooperation in the Visegrad group comprising Poland, Hungary, Slovakia and the Czech Republic should be based on common values.

Without naming names, Caputova - who took office last month - took aim at Hungary and Poland, the two eastern member states often in conflict with the EU over rule of law concerns.

“Our (V4) cooperation must also represent such values as the rule of law, democracy and freedom and such basic values of co-operation which are laid down in the founding treaty of the V4,” Caputova told a news conference. “So that we are not regarded as such who are weakening or dissolving the European Union.”

Hungarian Prime Minister Viktor Orban and Poland’s ruling Law and Justice (PiS) party have tightened controls on courts and judges, media and academics, as well as non-governmental groups. That has triggered conflicts with Brussels and alarmed rights groups worried they violate democratic principles, but they remain popular at home thanks to a tough line on migrants.

Caputova said on Thursday she was “convinced that the liberal democracy which guarantees everyone equal rights is the most effective tool for the protection of minorities.”

She also dismissed allegations by some pro-government Hungarian media that she was an agent working for Hungarian-born, U.S.-based billionaire George Soros as “lies”.

Orban’s government has been waging a campaign against Soros - who promotes liberal causes through his charities - for years.

Ader, an ally of Orban, sought to play down a rift, saying Hungary and Slovakia could differ on issues in the coming years.

“But I am sure that it will not make our co-operation impossible, neither on the bilateral and the V4 levels,” Ader added.