Conservatives within the EPP are calling for the expulsion of Orbán's Fidesz party | Attila Kisbenedek/AFP via Getty Images Internal pressure grows for EPP to expel Fidesz 4 parties call for Hungary’s ruling Fidesz to either be kicked out or suspended from center-right bloc.

Four national parties within the European People’s Party urged the political group’s president Thursday to either expel or suspend Hungary's Fidesz from the center-right bloc.

Three parties signed a letter to EPP President Joseph Daul asking for Fidesz’s expulsion — the Flemish Christian Democrats (CD&V), the Walloon Humanist Democratic Center (cdH) and Luxembourg's Christian Social People's Party (CSV), Luxembourgish MEP Frank Engel confirmed to POLITICO.

The fourth party, Portugal's CDS-People's Party, said it wrote to the EPP presidency, calling for Fidesz to either be expelled or suspended.

The letters follow the Hungarian government's decision to launch a public campaign against European Commission President Jean-Claude Juncker, a senior member of the EPP.

"Whoever continuously goes against [the] Christian-democrat ideology and values, doesn’t have a place with us," CD&V leader Wouter Beke tweeted when announcing the letter his party signed.

According to Portuguese newspaper Expresso, the CDS-People’s Party letter refers to internal problems caused by Fidesz within the EPP, which have "clearly and purposely broken the union" of the political family and its common objectives.

The differences that separate them "are too crucial to be maintained" and therefore deserve a response from all parties that make up the EPP, the Portuguese party added.

The Dutch Christian Democratic Appeal also said Thursday that its chairman told Daul there should be a discussion on Fidesz’s “position” within the group.

“Due to recent developments, we have to conclude that informal discussions with Fidesz no longer have the desired effect,” said CDA Chairman Rutger Ploum.

While tensions have been growing for months within the center-right bloc over Hungarian Prime Minister Viktor Orbán's party, leading members of the EPP are now publicly questioning Fidesz's future in the group.

Sweden’s Moderate Party recently indicated it will seek to have Fidesz expelled, while Finnish National Coalition Party leader Petri Orpo tweeted earlier this month that "those of us who are #EPP members, will consider the next steps in evaluating the EPP membership of Fidesz."

Ivo Oliveira contributed reporting.

This story has been updated.