WASHINGTON - 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, the Pentagon said on Thursday.

Last month, President Joe Biden quietly authorized Kyiv to launch U.S.-supplied weapons at military targets inside Russia.

But officials said at the time that Biden's decision applied only to targets inside Russia near the border with Ukraine's eastern Kharkiv region.

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.

The front lines in Ukraine have barely moved since the end of 2022, despite tens of thousands of dead on both sides in relentless trench warfare, the bloodiest fighting in Europe since World War Two.

After initial Ukrainian successes that saw Kyiv repel an assault on the capital and recapture territory in the war's first year, a major Ukrainian counter-offensive using donated Western tanks fizzled last year. Russian forces still hold a fifth of Ukraine and are again advancing, albeit slowly. No peace talks have been held for more than two years.

  - Reuters