Ukraine can use U.S.-supplied weapons to hit Russian forces that are firing on Ukrainian troops anywhere across the border into Russia and not just in Russian territory near Ukraine's Kharkiv region, Pentagon spokesman General Patrick Ryder said at a briefing on Thursday, according to Reuters.

Pentagon spokesperson Air Force Major General Patrick Ryder told reporters that while there had been no change in policy, Ukraine's use of weapons against Russian troops was not limited to near Kharkiv on the Russian side.

"The ability to be able to fire back when fired upon is really what this policy is focused on ... as we see Russian forces firing across the border, the ability for Ukraine to fire back at those ground forces using U.S.-provided munitions," Ryder said.

"It's self-defense and so it makes sense for them to be able to do that," he added.

Ryder's remarks echo comments made by Biden's national security adviser earlier this week.

"This is not about geography. It's about common sense," White House national security adviser Jake Sullivan told PBS. "If Russia is attacking or about to attack from its territory into Ukraine, it only makes sense to allow Ukraine to hit back against the forces that are hitting it from across the border."

Sullivan added that Ukraine could also use air-defense systems to fire at Russian planes flying in Russian airspace, if they are about to fire into Ukrainian airspace.