WATCH: Defense Secretary Austin, General Milley testify on defense budget in House committee hearing

Top U.S. defense officials defend the department’s budget before congress Wednesday, telling lawmakers the most urgent goal is sending the Ukrainians the capabilities they need along with an investment in capabilities that are “absolutely relevant to the competition with China.”

Watch the hearing in the player above.

Defense Secretary Lloyd Austin and chairman of the Joint Chiefs of Staff Gen. Mark Milley testifying before House Appropriations subcommittee comes as Congress is moving to pass a $40 billion Ukraine aid package that includes nearly $10 million in military equipment, weapons and training for Ukrainian forces as well as other NATO allies, particularly those on the eastern flank.

WATCH: As Ukraine regains territory near Kharkiv, Russia prepares for a more expansive war

There is another $8.7 billion to replenish U.S. military stocks that have been sent to Ukraine, through drawdown authority.

The funding passed the House Tuesday and is headed to the Senate.

“Our most urgent goal continues to be sending the Ukrainians the capabilities they need most right now as a war has shifted to the Donbas and to the south. The coming weeks will be critical for Ukraine,” Austin said.

Austin has called China the U.S. military’s leading long-term challenge but has been forced to focus heavily on Russia this year and regards China as increasingly dangerous amid concern that Beijing might provide military support for Russia’s war in Ukraine.

“We are now facing two global powers, China and Russia, each with significant military capabilities, both who intend to fundamentally change the current rules-based order,” Milley said.

He added, “we are entering a world that is becoming more unstable, and the potential for a significant international conflict between great powers is increasing, not decreasing.”

Austin, during his testimony when asked about the potential of Vladimir Putin’s intentions in Russia’s invasion into Ukraine, said the Russian president does not want to take on NATO in a military competition.

And said that Russia’s use of hypersonic weapons is not an indicator that Putin is willing to “elevate to use a nuclear weapon.”

Milley said there are no significant or game changing effects to date with the delivery of the small number of hypersonics that the Russians have used, “as Moscow struggles to achieve its objectives in Ukraine.”