BRUSSELS (AP) — The European Union’s top official said Monday that the allegations of corruption targeting a vice-president of the European Parliament are of “utmost concern” as she called for the creation of an independent ethics body covering all of the bloc’s institutions.

Belgian prosecutors charged four people over the weekend with corruption, being part of a criminal group and money laundering in connection with a major investigation into influence peddling at the European Union’s parliament.

The lobbying scandal has already seen parliament Vice-President Eva Kaili of Greece relieved of her duties. Authorities have not identified the Gulf country suspected of offering cash or gifts to officials at the parliament in exchange for political favors, but several members of the assembly and some Belgian media have linked the investigation to Qatar.

Qatar’s foreign ministry has denied any wrongdoing.

Ursula von der Leyen, the head of the European Commission, said the accusations against Kaili are threatening the confidence that EU citizens put in the 27-nation bloc’s institutions.

“This confidence and trust in our institutions need highest standards of independence and integrity,” von der Leyen told a news conference.

As lobbying activities at EU level lack comprehensive regulation, she said the independent ethics body she proposes would not only cover activities at the Commission, Council and Parliament, but also at the European Central Bank, European Court of Justice and European Court of Auditors.

“The principles of having such an ethics body where there are very clear rules on what has to be checked, how and when and what has to be published, how and when would be a big step forward,” she said.

The federal prosecutor’s office, without identifying any individual, said four of six people detained on Friday have been charged. The other two have been released.

Prosecutors have confirmed that one member of the Parliament was arrested but declined to confirm it is Kaili. They said they suspect “the payment of large sums of money, or the offer of significant gifts” to people holding strategic positions at the European Parliament capable of influencing decisions.

In Athens, Greek government spokesman Giannis Oikonomou said the case of Kaili “is a very serious case that is in the hands of Belgian justice.”

The case, he said, “creates one more rift in the credibility and trust in European institutions and the European Parliament.”

The scandal broke as the EU Parliament begins its last plenary session of the year in Strasbourg, France, later on Monday.

Manon Aubry, the Left group’s co-president at Parliament, said that her group will ask for a debate and a resolution on the scandal, with the aim of implementing “way stricter rules.”

“The battle continues: Our democracy is not for sale,” she said on Twitter.

European Parliament president Roberta Metsola relieved Kaili, a 44-year-old former TV news anchor, of her duties over the weekend. Kaili also was suspended by her party in Greece and the EU assembly’s Socialists and Democrats group on Friday after the raids, in which police also seized around 600,000 euros ($633,500) in cash, computer equipment and mobile telephones.

Kaili’s party in Greece, the Socialist Pasok-Movement for Change, publicly distanced itself from remarks she made in the EU parliament last month praising Qatar, which is currently hosting soccer’s gala event, the World Cup.

Qatar has come under heavy international pressure to introduce labor reforms in recent years as it sought to build new World Cup stadiums in record time, often using migrant workers who toiled for long hours under harsh conditions.

The EU and Qatar have strengthened their economic relationships since the start of Russia’s war in Ukraine. As European countries have supported Ukraine after Russia’s invasion in February, Moscow has slashed supplies of natural gas used to heat homes, generate electricity and power industry.

That has created an energy crisis that is fuelling inflation and increasing pressure on companies as prices have risen, with the EU looking for alternatives to buy liquefied natural gas on a long-term basis, notably in Qatar.

In April, the European Commission also proposed to lift visa requirements for short stays in the region for nationals of Qatar.