China's military said on Wednesday it sent fighter jets to monitor and warn a U.S. Navy patrol aircraft that flew over the sensitive Taiwan Strait, a mission that took place weeks before Taiwan holds elections.

China claims sovereignty over democratically governed Taiwan, and says it has jurisdiction over the strait. Taiwan and the United States dispute that, saying the Taiwan Strait is an international waterway.

The U.S. Navy's 7th Fleet said the P-8A Poseidon maritime patrol and reconnaissance plane, which is also used for anti-submarine missions, flew over the strait in international airspace.

"The aircraft's transit of the Taiwan Strait demonstrates the United States' commitment to a free and open Indo-Pacific. The United States military flies, sails and operates anywhere international law allows," it said in a statement.

China's military described the flight as "public hype", adding it had sent fighters to monitor and warn the U.S. plane and "deal with it in accordance with the law and regulations".

"Troops in the theatre are always on high alert and will resolutely defend national sovereignty and security as well as regional peace and stability," the Eastern Theatre Command of the People's Liberation Army said in a statement.

Taiwan's defence ministry said its forces monitored the U.S. aircraft as it flew in south through the strait, and described the situation as "normal".

The last time the U.S. Navy announced a Poseidon had flown through the strait, in October, China said it had sent fighter jets to monitor and warn the aircraft.

Taiwan is gearing up for presidential and parliamentary elections on Jan. 13, which China has cast as a choice between war and peace.

China has stepped up its military activity around Taiwan in the past four years, including staging two rounds of major war games over the last year and a half. (Reporting by Beijing newsroom; Additional reporting by Ben Blanchard in Taipei; Editing by Kim Coghill and Gerry Doyle)