BRUSSELS (AP) — The European Union’s administrative watchdog is trying to find out how a top transport official was permitted to fly to Qatar with tickets paid for by the government there, as a major corruption scandal linked to the Gulf state roils the bloc’s parliament.

In a letter made public on Monday, European Ombudsman Emily O’Reilly noted that the head of the European Commission’s transport department, Henrik Hololei, had “traveled a number of times between 2015 and 2021 at the expense of the Qatari government or organizations that are close to it.”

The trips were made when the department, known as DG MOVE, was involved in negotiating an EU-Qatar air transportation agreement, which was signed on Oct. 18, 2021. Hololei didn’t take part in the negotiations, but did lead the department conducting them.

O’Reilly asked European Commission President Ursula von der Leyen how the paid flights were authorized by the EU’s executive branch and how many other commissioners or senior officials have had their travel expenses reimbursed by non-EU countries or organizations since January 2021.

“The Qatari government and organizations close to it paying for travel expenses for DG MOVE’s most senior official gives rise to legitimate questions around possible undue influence of the EU’s decision-making in this area,” O’Reilly wrote.

“Whilst such missions may further the interest of the EU, it is of the utmost importance that these arrangements are scrutinized in order to manage the risks of conflicts of interest, whether real, potential or perceived,” she added.

A commission official insisted on Monday that Hololei’s travel expense payments respected the rules on conflicts of interest in place at the time. Those rules, however, foresaw that Hololei himself should judge whether there were any ethical issues posed by his travel arrangements.

“The conclusion that he drew was that there was no conflict of interest,” commission spokesman Balazs Ujvari told reporters. Ujvari also confirmed that Hololei had benefited from paid accommodation during some of his trips, without providing details.

Asked whether the commission believes that Hololei should resign, another official, Dana Spinant, said only that the transport chief’s actions were “in line with the rules applicable at the time.”

Both officials underlined that a review of the rules was launched late last year and that the revamp could address such ethical concerns. They said that, as far as they were aware, no other senior members of the EU’s executive branch benefited from similar paid travel.

The ombudsman’s inquiry comes four months after four people were charged with corruption, money laundering and membership in a criminal organization for allegedly accepting bribes from Qatari and Moroccan officials to influence proceedings at the European Parliament.

Both countries deny being involved but the EU parliament has suspended work on all Qatar-related files, including on an agreement to ease visa restrictions for some Qatari nationals, until an investigation is completed.