MANILA The Philippines and Japan held their first joint military exercises in the South China Sea on Friday, the Philippine armed forces said, in the latest collaboration between countries that have pushed back against China's regional assertiveness.

The drills, which took place within the Philippines' exclusive economic zone, followed similar exercises between Manila and Washington on Wednesday.

"This activity was part of the ongoing efforts to strengthen regional and international cooperation towards realising a free and open Indo-Pacific," the Armed Forces of the Philippines (AFP) said in a statement.

The Philippines and Japan, both US allies, last month signed a landmark military pact allowing deployment of forces on each other's soil.

China claims as its territory much of the South China Sea, a conduit for the bulk of northeast Asia's trade with the rest of the world in which Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.

Japan, which announced last year its biggest military build-up since World War Two in a step away from post-war pacifism, does not have any claims to the busy waterway.

But it has a separate maritime dispute with China in the East China Sea, where the neighbours have repeatedly faced off.

The latest exercise, which included two vessels from each side, included a communications exercise, tactical manoeuvring, and a photographic exercise, the AFP said.

  - Reuters