The Associated Press formally cooperated with Hitler’s Nazi regime, including providing material produced by the Nazi’s propaganda ministry, a German historian reports in a new study.

The AP was the only international news agency allowed to continue to operate in Germany, until the United States entered World War II in 1941.

Historian Harriet Scharnberg, in an article published in German in the academic journal Studies in Contemporary History, shows that The AP was able to remain in Germany due to its two-way cooperation with the Nazi regime.

The article was first reported in the Guardian.

The AP agreed to abide by the Schriftleitergesetz, or Editor’s Law, under which it agreed not to publish any material “calculated to weaken the strength of the Reich abroad or at home.”

Among other cooperations, the AP hired reporters and photographers who also worked for the Nazi propaganda ministry.

The news service also allowed the Nazis to use its photo archives to create anti-Semitic propaganda.

Scharnberg, a historian at Halle’s Martin Luther University, argued that AP’s cooperation with the Hitler regime allowed the Nazis to “portray a war of extermination as a conventional war,” according to the Guardian.

The study calls into question the AP’s current relationship with totalitarian regimes. For example, according to the Guardian, regarding North Korea, questions have repeatedly been raised about the neutrality of its bureau there.

“As we continue to research this matter, AP rejects any notion that it deliberately ‘collaborated’ with the Nazi regime. An accurate characterization is that the AP and other foreign news organizations were subjected to intense pressure from the Nazi regime from the year of Hitler’s coming to power in 1932 until the AP’s expulsion from Germany in 1941. AP management resisted the pressure while working to gather accurate, vital and objective news in a dark and dangerous time,” an AP spokesman told the Guardian.