China reportedly conducted combat patrols over man-made islands in the South China Sea, an area where an international court recently ruled that they have no territorial claim.

Several H-6 bombers and Su-30 fighter jets flew missions around the Spratly Islands, including surveillance flights and aircraft refueling, Reuters reported. A senior Chinese military official said that the missions were meant to normalize these types of drills in the region and respond to security threats.

It is not clear when these operations occurred.

China has built up several islands in the South China Sea, ignoring other countries' territorial claims to that area, including those of Brunei, Malaysia, the Philippines, Taiwan and Vietnam. The Hague ruled last month that China does not have a territorial right to the South China Sea.

The U.S. conducts freedom of navigation operations around that area in an effort to show that it is an international waterway, not sovereign waters. Lawmakers on Capitol Hill have repeatedly urged the U.S. military to do more of these operations.