Biden’s comments come a week after Ukrainian soldiers launched a surprise attack in the border region of Kursk that has left a swathe of Russian territory under Kyiv’s control.

Finally breaking his silence over the operation, Biden said U.S. officials were in close contact with Ukraine over the invasion.

The White House said Kyiv did not provide any advance notice of its incursion and the United States had no involvement in the operation.

However, Russian officials claimed that Kyiv’s Western allies must have known about the attack.

A U.S. official said the goal of the Kursk incursion appeared to be to push the Kremlin to pull troops out of Ukraine to defend Russian territory against the cross-border assault.

Meanwhile, the Pentagon’s press secretary said at a briefing on Tuesday that the U.S. Department of Defense was not commenting on Ukraine’s offensive operation, according to Ukrinform, Ukraine’s state news agency.

“That’s really something for the Ukrainians to talk to. I’d refer you to them to talk about their operations,” Maj. Gen. Patrick Ryder said when asked whether Washington sees the Ukrainian offensive in the Kursk region as a military operation or a raid.

The assault in Kursk, which marks the first invasion of Russia by a foreign force since World War II, has changed the narrative around the campaign waged by the Kremlin against Ukraine.

Putin ordered thousands of troops into Ukraine in February 2022. Russia had been advancing since Kyiv’s 2023 counteroffensive failed to make any major gains against Moscow’s forces.