The U.S. so far deems Ukraine's surprise incursion into Russia's Kursk region a protective move appropriate for Kyiv to use U.S. equipment, officials in Washington said, but they expressed worries about potential complications as Ukrainian troops push further into enemy territory.
U.S. officials said Kyiv's overarching goals remain unclear.
"It complicates the policy the more they progress into Russia without defined terms," a U.S. official, speaking on the condition of anonymity, told Reuters.
The official said that if Ukraine starts taking villages and other non-military targets using U.S. weapons and vehicles, that could raise questions about whether it is within the limitations Washington has imposed.
A second U.S. official said Washington's weapons policy was not designed for Ukraine to invade Russia, although Kyiv was technically in compliance. As a result, the official said, President Joe Biden's administration has not taken a strong public stance in support of or opposition to the assault.
It was unclear which U.S.-made weapons or equipment have been used in the incursion. The Pentagon said last week that Ukraine was "taking actions to protect themselves from attacks that are coming from a region that are within the U.S. policy."
Since Russia invaded its neighbor in February 2022, the U.S. has stood firm with Ukraine, providing more than $50 billion worth of military equipment. Seeking to avoid a broader conflict with geopolitical rival Russia, the Biden administration initially put strict limits on use of its weapons.
"We have been very, very clear and consistent that we really want to see Ukraine focus on defending themselves against this aggression inside of course their borders," White House national security spokesman John Kirby told MSNBC on Thursday.
"We don't encourage and we don't enable attacks outside of Ukraine except for in those exigent circumstances where we believe just over the border they're facing some imminent threats," he said.
ESCALATION
The administration is working to determine what Ukraine's goals actually are with the offensive, which the U.S. officials said caught Washington by surprise. One official said: "It's not unusual for them to do things without letting us know."
One possible aim of the operation, they said, appeared to be to force Russia to pull some troops out of Ukraine. One official said intelligence indicated at least some movement of Russian troops from Ukraine's Kharkiv towards the Kursk region.
The gambit looks like it is starting to pay off, but "we'll have a clearer picture in the weeks ahead," said one U.S. official. Biden has not spoken with Zelenskiy since they met twice in June in France and Italy, the official said.
On Thursday, Russia said it would beef up border defenses, improve command and control and send in additional forces following the incursion into Kursk. Moscow has also warned against the use of Western weapons by Ukraine.
"The use of U.S. weapons in Kursk, in Ukraine or anywhere else - for us - is an act of escalation and it will have serious consequences, we are being absolutely blunt about this with our U.S. colleagues. They know our opposition," Russia's Deputy U.N. Ambassador Dmitry Polyanskiy told reporters on Wednesday.
The Ukrainian and Russian militaries have banned international journalists from the battlefield making it all but impossible to verify their claims about the battle.
The U.S. has gradually eased restrictions on Ukraine's use of its weapons in part because Russian President Vladimir Putin has not lashed out as feared against Europe or the U.S., experts said.
"The Biden administration sees that they've been able to manage the escalation ladder extremely effectively since the outset of the war," said Rachel Rizzo, a senior fellow at the Atlantic Council's Europe Center in Washington.
Rizzo said the goal was to manage Russia's reaction, but also "allow the Ukrainians enough leeway in terms of weapons use that they have an opportunity to actually see some advances."
