Romania has arrested Israelis on charges of spying on and trying to intimidate the country’s chief anti-corruption prosecutor, officials say.

Four Israelis, at least two of them former Mossad agents, have been arrested for spying on and intimidating Romanian anti-corruption prosecutor Laura Codruta Kovesi.

The Israeli company Black Cube has been spying on 20 Romanian officials with ties to the government, as well as on prominent business figures, Romanian reports said.

“There is no doubt that this is a matter of national security,” the head of Romania’s Anti-Terror Authority said. “It’s a real threat to heads of the Romanian government when a woman in a position like this receives threats on her life. All the security apparatuses in Romania will have to improve to prevent incidents like these.”

Among four suspects arrested there is one Israeli citizen – Ron Weiner. Another suspect, David Geclowicz, was identified by Romanian media as an Israeli national as well, but holds Belgian citizenship.

The two men had their remands extended by 30 days on Wednesday on charges of information fraud and harassment for allegedly spying on Laura Codruta Kovesi, the chief prosecutor of Romania’s National Anti-corruption Directorate (Direcţia Naţională Anticorupţi).

Reports in Romanian media stated that the suspects “established an organized network to carry out serious crimes, including cyber crimes, attempts to steal information, and email hacking.”

“An investigation has been launched and two people have been arrested,” Mihaela Porime, a spokeswoman for the anti-crime and terrorist prosecutors’ office, said on Wednesday, adding that the suspects work for the Israeli private intelligence agency, Black Cube.

The Black Cube website describes the company – which has offices in Tel Aviv, Paris and London – as “a select group of veterans from the Israeli elite intelligence units that specializes in tailored solutions to complex business and litigation challenges.”

In a statement released in response to the reports, the company says its employees were themselves investigating claims of corruption by the Romanian government. ”Recently, the company undertook a project in Romania to collect evidence of serious corruption in the Romanian government and its agencies. Whilst performing this work, two of the company’s employees were arrested after having made significant discoveries,” the statement read.

The website listed the late Meir Dagan, a former Mossad head, as honorary president of its advisory board.

Israel, however, has said that the arrests will not impact Israel and Romania ties.

Israel and Romania have excellent relations, and the recent arrest of two Israelis working for a private firm for allegedly spying on a senior Romanian official will not impact on those ties, a diplomatic official in Jerusalem said.

According to the official, the Romanian government understands that the Israelis, identified as Ron Weiner and David Geclowicz who work for a company called Black Cube, are private citizens and were acting in a private capacity.

If a Romanian national is arrested in Israel, the official said to illustrate his point, Jerusalem does not hold Romania responsible.