That's according to Reuters, Ukrinform reports.
Austin said the United States was concerned about advances by Russia in Ukraine, to which U.S. security assistance would continue.
He said he was encouraged by Ukraine's ability to recruit more people to beef-up its own ranks.
"I applaud what the Ukrainians continue to do to make sure that they can hold their own," he said.
"The Ukrainians are very determined people," Austin said.
Read also: Austin announces new USD 2.3 B defense package at meeting with UmerovAccording to British intelligence, Russian forces will continue their tactical advance on the eastern front in the coming weeks.