Mr Trump described the force as an “armada” and said that submarines were being sent which were “far more powerful than the aircraft carrier.”
China and Russia have dispatched spy vessels to shadow a US aircraft carrier group heading to North Korean waters, Japanese media said, amid rising tensions over Pyongyang’s nuclear ambitions.
Beijing sought Russian help in averting a crisis over North Korea last week, as concerns grow in China that Donald Trump is seeking to confront Ngorth Korea over its weapon’s program.
The US president sent a navy group led by the aircraft carrier Carl Vinson into the region, in what is being seen as a signal to Pyongyang.
Mr Trump described the force as an “armada” and said that submarines were being sent which were “far more powerful than the aircraft carrier.”