The leaders of the Japanese and German air forces pledged Thursday to further enhance cooperation at a time of rising tensions in the Asia-Pacific region, with their fighter jets conducting a formation flight over Japanese skies the previous day.

A more assertive China has led to increased tension in East Asia, particularly with regards to Taiwan. Germany has been stepping up its engagement in the Indo-Pacific region, partly propelled by Beijing's actions, which some countries have said undermines the rule of law, human rights and democracy.

"We will deepen our collaboration and further promote efforts between the two air forces to maintain and strengthen a free and open Indo-Pacific," said Gen. Shunji Izutsu, chief of staff of the Air Self-Defense Force, at a joint news conference in Tokyo.