Two U.S. bombers flew over the contested South China Sea on Thursday, a show of force in light of China’s insistence that it controls much of the international waters, the U.S. Air Force told one outlet Friday.

The Air Force directed two B-1B Lancer bombers from Guam to make the flight, following a similar flight they made over the same sea last month. The move was directed as President Trump prepares for his meeting with Chinese President Xi Jinping while at the G-20 summit in Hamburg, Germany.