US, German and EU officials publicly endorsed Ukraine’s ongoing military ground offensive inside Russia’s Kursk region Thursday, as Ukrainian forces appeared to continue to gain ground.

On Tuesday, highly-trained Ukrainian army and special forces units launched a ground offensive into Kursk, near the Ukrainian border, using American Stryker and German Marder armored vehicles.

To date, the Ukrainian forces have seized 350 square kilometers of territory in an offensive including at least 1,000 forces and likely more. Although this is the third Ukrainian offensive inside Russia since the Russian invasion of Ukraine in February 2022, it is the first using regular Ukrainian army troops and is by far the largest to date.

On Thursday, US officials publicly backed the Ukrainian attack on Kursk, which contradicted previous US claims not to support attacks on Russian territory.

Ukraine’s attack is “consistent with our policy,” said US Defense Department Deputy Press Secretary Sabrina Singh at a briefing Thursday.

Singh claimed that Kursk was being used to launch attacks on Ukraine, claiming that the US has “supported Ukraine from the beginning to defend themselves against attacks that are coming across the border.”

She repeated that the assault on Russia was being carried out by Ukraine “to protect themselves from attacks,” adding that Kiev is operating “within the US policy of where they can operate our weapons, our systems, our capabilities.”

State Department spokesman Matthew Miller likewise defended the offensive, saying, “Yes, in the area where they are currently operating across the Russian border, we have seen attacks come from there.”

These statements were mirrored by a spokesman for Germany’s defense ministry, which told the Financial Times that the “German government’s declared objective is to support Ukraine in its fight against the Russian aggressor.”

The European Commission, for its part, said Thursday that Ukraine had a “right to defend itself” and that this “includes hitting the enemy on its territory.”

Ukrainian forces were seen operating as far as 18.5 miles behind the Russian border Thursday. The attack triggered a state of emergency and widespread evacuations.

In a statement Thursday, Russia’s Ministry of Defense claimed to have repelled the attack. It announced that approximately 1,000 soldiers were involved in the attack and that the Ukrainian military had lost 600 soldiers and 82 vehicles. “Air strikes are being carried out on advancing reserves of the armed forces of Ukraine on the territory of the Sumy region,” the Ministry of Defense said.

But battles continued to rage throughout the day, with footage showing low overflights by fighter aircraft and widespread damage throughout the region.

According to a report by the Institute for the Study of War on Wednesday, Ukrainian forces had captured 11 settlements.

Ukrainian President Volodymyr Zelensky made a veiled reference to the attacks Thursday, saying “the more pressure is exerted on Russia—on the aggressor that brought the war to Ukraine, the closer peace will be. Just peace through just force.”

An op-ed in the Telegraph gloated that “Ukraine’s offensive operations in Kursk show no sign of slowing down.” It continued:

Overnight, Ukrainian forces reportedly seized control of Sudzhna, reached the outskirts of Korenevo, and advanced northward to Malaya Loknya. In less than forty-eight hours, Ukraine has captured more territory than during the entire ill-fated summer 2023 counter-offensive.

The op-ed added, “With F-16 jets also arriving on the frontlines, Putin has plenty of reasons to worry.”

This was a reference to the official introduction of US-made F-16 fighter jets onto the battlefield, which this week began flying combat missions.

The Washington Post, for its part, reported that “Ukrainian officials have asked Washington to let them use long-range US ATACMS missiles to hit airfields that Russia is using to retaliate against the incursion—a decision that, if approved, could allow Kyiv to hold a portion of Kursk for some time.”

The offensive follows the NATO summit in Washington, which concluded with a plan to transfer the coordination of international military hardware and logistics to the direct control of NATO.

In April, the Biden administration began supplying Ukraine with long-range ATACMS missiles, which have a 300-kilometer (186-mile) range, while claiming they would not be used for strikes inside Russia itself.

In May, US National Security Adviser Jake Sullivan asserted that the US is allowing Ukraine to use US-provided weapons to strike “anywhere” inside Russian territory.

Despite the significant offensive in Kursk, the Ukrainian front line in Donetsk, the main battlefield of the war, is on the brink of collapse, amid growing popular opposition to the war inside Ukraine and a major shortage of manpower. Under these conditions, the US and NATO are removing remaining restrictions on their direct role in the war.

Whatever the broader military significance of the Kursk offensive, it is now the case that German and American armored vehicles, piloted by Ukrainians, are being driven over the Russian border and are being used to launch attacks on Russia, in a significant and dangerous escalation of NATO’s involvement in the conflict.