Two U.S. Air Force B-52H Stratofortress bombers flew into the South China Sea this week on training missions. Photo by Airman 1st Class Gerald R. Willis/U.S. Air Force
Sept. 27 (UPI) -- The U.S. Air Force flew two more B-52H Stratofortress bombers into the highly disputed South China Sea this week.
Beijing has kept quiet about the flights into contested waters but U.S. Secretary of Defense James Mathis said there's nothing out of the ordinary about it.
"That just goes on. If it was 20 years ago and they had not militarized those features there it would have just been another bomber on its way to Diego Garcia or whatever," Mattis said.
Officials said the U.S. Air Force flew four more flights last month.
Pacific Air Forces Public Affairs said the flights have been going on since 2004 and they are "consistent with international law and United States's long-standing and well-known freedom of navigation policies."
The first bomber from the 96th Expeditionary Bomb Squadron conducted training exercises in the South China Sea and Indian Ocean on Sunday. Another occurred Tuesday.
Officials said the bomber flights were escorted by Japanese fighter jets and flew in close proximity to the Senkaku Islands, which China claims. The planes also flew into the Chinese Air Defense Identification Zone in the area.
Though Beijing hasn't responded to the flights, tensions between the United States and China are at an all-time high.. President Donald Trump has imposed new tariffs on Chinese imports and Beijing has retaliated with its own tariffs on U.S. goods.
On Wednesday, Trump accused China of trying to interfere in the 2018 midterm elections, a move he said is meant to hurt politicians who support him.
"They do not want me or us to win because I am the first president ever to challenge China on trade," Trump said. "We are winning on trade."
Chinese officials deny meddling in the election.