BEIJING — In a show of strength before an international court’s ruling on China’s claims in the South China Sea, the United States Navy sent two aircraft carriers and their accompanying ships on training drills in the western Pacific Ocean on Saturday.

The carriers John C. Stennis and Ronald Reagan sailed close together in the Philippine Sea as part of air defense and sea surveillance operations that involved 12,000 sailors, 140 aircraft and six smaller warships, the United States Pacific Fleet in Hawaii said in a statement.

“We must take advantage of these opportunities to practice war-fighting techniques that are required to prevail in modern naval operations,” Rear Adm. John D. Alexander said in a statement.

The operations occurred on the eastern side of the Philippines, in a body of water that is not adjacent to the South China Sea but is close, a spokesman for the Pacific Fleet said. China seeks to dominate the western Pacific Ocean as part of its long-term strategy, American strategists say.