US Secretary of Defense James Mattis said that Russia and China are challenging the united states’ military dominance with technological advances in sea, land and air weapons systems.

Mattis delivered the statement to the committee as part of his testimony at a hearing on the defense department’s 2018 budget request.

The US defense chief also said US dominance of the air is challenged by the “proliferation of advanced integrated air defense networks and 5th-generation aircraft.”

Mattis noted said these developments put the entire international order at risk.

The defense department has requested a 639 billion dollars budget for next year.