BUDAPEST - The European People's Party (EPP) has raised security concerns over a decision by Hungary to ease visa restrictions for Russian and Belarusian citizens, fearing it could fuel espionage in the EU, according to a letter seen by Reuters on Tuesday.

Manfred Weber, chair of the centre-right EPP, has written to European Council head Charles Michel to say the new Hungarian rules could "create grave loopholes for espionage activities... posing a serious risk to national security".

"This policy could also make it easier for Russians to move around the (borderless) Schengen area, bypassing the restrictions required by EU law," Weber said in his letter.

The letter was first reported by the Financial Times.

The Hungarian government did not immediately respond to an emailed request for comment.

Michel's office had no comment on the letter, which highlights tensions between EU institutions and Hungary, current holder of the bloc's rotating presidency, as it seeks to maintain cordial ties with Russia despite the Ukraine war.

A European Commission spokesperson said it would be in touch with Hungary regarding the new rules, and that Budapest was bound to check whether they complied with Schengen regulations.

Hungary this month extended its "national card" immigration programme to include Russians and Belarusians, among others. The holder of such a card is allowed to work in Hungary without security clearance and can bring their families to the country. It is valid for two years but can be prolonged.

Officially, the card holder is not a guest-worker and so does not appear in statistics and different national quotas either.

Hungary's visa decision came a year after the United States imposed sanctions on three top officials of the International Investment Bank, a Russian-controlled bank in Budapest: two Russians and a Hungarian.

Bank employees had enjoyed full diplomatic immunity and could travel freely in the EU. Under U.S. pressure, Hungary withdrew from the IIB but expressed frustration at having to do so.

This month Hungarian Prime Minister Viktor Orban, who took over the six-month EU presidency on July 1, infuriated his EU partners by visiting Moscow to discuss a potential Ukrainian peace deal with Russian President Vladimir Putin.

Orban has strongly criticised Western military aid to Ukraine.

  - Reuters