BERLIN (AP) — European Commission President Ursula von der Leyen defended the use of external experts during her time as German defense minister as she testified Thursday before a parliamentary inquiry, but conceded that mistakes were made.

Von der Leyen, a fixture in Chancellor Angela Merkel’s Cabinets for nearly 14 years, was Germany’s defense minister from late 2013 until her unexpected nomination in July to lead the European Union’s executive commission. Her tenure as defense chief drew mixed reviews, and a parliamentary inquiry has been looking into questions about whether proper procedures were followed in the expensive appointment of outside experts at the ministry.

Von der Leyen conceded that there were breaches of the rules on awarding contracts, but insisted that bringing in outside experts was necessary. She said that work on digitizing the military, in particular, “couldn’t be done without help from outside,” news agency dpa reported.

She added that the defense ministry has always used support and advice, and will need to in the future as well.

Opposition lawmakers also have raised questions about the deleting of data on two cellphones von der Leyen used — one that was replaced in January 2019 and a second that she used after that. Von der Leyen has said she handed the phones back to the ministry and wasn’t aware of the data being deleted.

Von der Leyen’s appearance is meant to conclude testimony after about a year, during which the panel has heard about 30 witnesses.