"We need to be prepared for long haul to stand with Ukraine for as long as it takes," Stoltenberg said at the start of his meeting with Austin at the Pentagon.
To date, the US and NATO countries have delivered billions in weapons packages to Ukraine amid the ongoing conflict, with the combined assistance including over two dozen different types of hardware.
More recently, the US announced it would be sending over its Abrams tanks but kept quiet on the matter of sending over its F-16. Earlier this year, White House National Security Council spokesperson John Kirby explained the US did not need to fork over the fighter jets on account of Kiev already being given earlier arms.
However, of concern for the NATO secretary-general was the effect the Ukraine conflict may have on the Indo-Pacific region - more specifically, China.
"Beijing is watching [Ukraine] closely and learning lessons that may influence its future decisions. So what happens in Europe today could happen in Asia tomorrow," Stoltenberg said during a news conference.
NATO allies have "real concerns" about China, including a recent military and nuclear force buildup, Stoltenberg said. China has also increased intelligence gathering activities in Europe, he noted said.
Stoltenberg also said he discussed those concerns with US Secretary of State Antony Blinken during an earlier meeting Wednesday in Washington.
Beating the war drum against Russia, the NATO official proceeded to accuse Russia of looking to launch a new military offensive ahead of the one year anniversary of its special military operation.
"We see no sign that Russia is preparing for peace, on the contrary, remarked during a joint conference with Blinken.
Russia's special military operation in Ukraine was a key topic of discussion, along with China, in the meeting between Stoltenberg and Blinken earlier in the day. Stoltenberg emphasized the NATO allies must continue to provide Ukraine with the weapons it needs to defend itself from Russia.
Russia has repeatedly condemned foreign military aid provided to Ukraine and warned that any arms shipments on Ukrainian territory would be legitimate targets for its forces.