Leijtens takes over from Frontex’s interim director Aija Kalnaja, who took over in July after the resignation of her predecessor Fabrice Leggeri, who was accused by human rights groups of failing to stop illegal migrant pushbacks.

The EU’s anti-fraud office OLAF said on Friday that it was investigating Frontex, without giving further detail.

Kalnaja said that she was “notified by OLAF that I am a person of concern in one case, which consists of two separate events”.

She said she would “cooperate with OLAF fully, openly and unconditionally to clarify the facts”.

Leijtens was congratulated on Tuesday by EU home affairs commissioner Ylva Johansson, who thanked Kalnaja “for her excellent leadership during a difficult period”.

“We are committed to continue improving Frontex governance, to best protect the EU external border,” Johansson said.

Leijtens has been head of the Royal Netherlands Marechaussee, which carries out military and civilian police duties, since 2019.

His Frontex role has a five-year mandate.