Explained | What to know about Ukraine’s cross-border assault into Russia

Ukraine pressed ahead with its assault inside Russian territory Tuesday, a week into the biggest foreign incursion into the country since World War II.

While Russian military officials Tuesday insisted that the situation was under control, Aleksei Smirnov, acting governor of Russia’s Kursk region, where Ukraine mounted its incursion, warned that “the crisis has not yet been overcome.” And President Volodymyr Zelenskyy of Ukraine said Tuesday on social platform X that “our forces continue to advance in the Kursk region.”

Col. Roman Kostenko, a member of Ukraine’s parliament serving in the country’s military, told a local news outlet that the “advance is ongoing.”

The cross-border attack caught Russia by surprise and signified a shift in tactics for Ukraine more than two years after Moscow’s troops poured across Ukraine’s border in a full-scale invasion.

The rapid advance by Ukrainian forces has been an embarrassment for the Kremlin and aims to alter the narrative of the war at a time when Ukraine’s forces are stretched thin on the front lines of their own country.

Here’s what to know about Ukraine’s cross-border operation in Russia.

What happened?

Ukrainian troops and armored vehicles stormed into the Kursk region of western Russia the morning of August 6, punching through border defenses and seizing several settlements in heavy fighting that left a trail of death and ruin.

The assault opened a new front in the 30-month war and did not just catch Russia off guard: Some Ukrainian soldiers and US officials also said they lacked advance notice.

Russia’s top general estimated that Ukraine had deployed 1,000 soldiers for the incursion, while US officials said Ukraine had sent several thousand. Military analysts have said the attack involved elements of at least four brigades in a rare example of a successful operation involving support from artillery, air defenses and electronic warfare. That translated into quick advances on the ground.

How far into Russia have Ukrainian troops advanced?

Ukrainian forces advanced several miles into Russia within the first 24 hours of the incursion.

By Monday, Smirnov said that 28 towns and villages were under Ukrainian control. Ukrainian troops had pushed 7 miles into Russian territory along a 25-mile front, he said, adding that 12 civilians had died in the fighting.

His claims could not be independently verified, though the description of the extent of Ukraine’s advance was roughly in line with analysts’ estimates.

The head of Ukraine’s armed forces, Gen. Oleksandr Syrsky, on Monday claimed Ukraine had control of “about 1,000 square kilometers,” or just under 400 square miles. Zelenskyy said Tuesday on X that “74 communities are under Ukrainian control,” though that could not be independently verified.

Why is this significant?

Ukraine has regularly bombarded Russian oil refineries and airfields with a fleet of homemade drones since Moscow’s full-scale invasion began. It has also helped stage two other ground attacks. Those, however, were smaller forays into Russia by Russian exile groups backed by the Ukrainian army and ended in quick retreats.

Until last week, Ukrainian forces had not counterattacked into Russia. The gains in Kursk are the quickest for Ukrainian forces since they reclaimed the Kherson region of their own country in November 2022.

How has the Kremlin responded?

As Ukrainian forces pushed deeper into Russia, Moscow scrambled to shore up its defenses, and President Vladimir Putin convened his security services to coordinate a response.

The Russian military said it was sending more troops and armored vehicles to try to repel the attack, with Russian television broadcasting images of columns of military trucks. Russia has begun to withdraw small numbers of troops from Ukraine to try to help repel the Ukrainian incursion, a US official said Tuesday without describing how many Russian troops were involved or what impact the reinforcements might have.

While the efforts appear to have helped stall further advances by Ukrainian troops, Ukraine’s forces are holding ground a week into the incursion. They claimed Saturday to have captured a small village in the neighboring Belgorod region, and analysts say their forces control most of the Kursk town of Sudzha, about 6 miles from the border.

Russian officials and the state news media have repeatedly claimed to have the situation under control — most recently Tuesday — only to then lose more ground.

“The operation to neutralize” Ukrainian units, Russia’s Ministry of Defense said Tuesday, “is in progress.”

And what about Putin?

The incursion has embarrassed Putin and his military establishment, prompting questions about Russia’s level of preparedness.

Underscoring how the surprise attack rattled the Kremlin, Putin lashed out at the West in a tense televised meeting with his top officials Monday.

“The West is fighting us with the hands of the Ukrainians,” he said, repeating his frequent depiction of the war, which he started, as a proxy campaign against Russia by the West. “The enemy will certainly get the response he deserves, and all our goals, without doubt, will be accomplished.”

Putin directed his military to push out Ukraine’s troops and to work with the border guard service to “ensure the reliable protection of the state border” — an acknowledgment that Russia had failed in that regard.

What has Ukraine said?

It took days for Ukraine to publicly acknowledge the cross-border operation, with the military staying silent in the face of accusations and statements from Russian officials.

Zelenskyy’s most explicit reference to the Kursk region incursion came only Monday night, when he said that Russia had launched attacks from the area.

“Therefore, our operations are purely a security matter for Ukraine,” he said in his nightly address. But he also hinted at another rationale, adding: “Russia brought war to others, and now it’s coming home.”

What is the goal of Ukraine’s incursion?

Analysts say that Ukraine’s offensive most likely has two main aims: Draw Russian forces from the front lines in eastern Ukraine and seize territory that could serve as a bargaining chip in future peace talks.

The operation could also offer a much-needed morale boost for Ukrainians, whose forces have been losing ground to Russian troops for months.

But military analysts have questioned whether Kyiv’s cross-border assault is worth the risk, given that Ukrainian forces are already stretched on the front lines of their own country, including suffering from shortages of troops and ammunition.

How is it affecting the fight inside Ukraine?

Russian forces have been pummeling Ukrainian forces in the east even as Moscow races to respond to the incursion into the Kursk region, according to Ukrainian military officials.

And there is little indication so far that Russia is redirecting front-line forces from eastern Ukraine. Instead of pulling those brigades, Russia appeared to be redeploying lower-level units to the Kursk region, according to a briefing Sunday by the Institute for the Study of War, a US-based research organization.

While Kyiv’s allies have in the past been wary that Ukrainian incursions in Russia could escalate the war, the United States has suggested that the assault in the Kursk region does not violate American guidance.

However, senior American officials have said privately that they understood Kyiv’s need to change the optics and the narrative of the war but that they were skeptical Ukraine could hold the territory long enough to force Russia to divert significant forces from the front lines in eastern and southern Ukraine.

What happens next?

Heorhii Tykhyi, a spokesperson for Ukraine’s Foreign Ministry, told local news outlets Tuesday that the country was “not interested in taking territory in Kursk region,” echoing Zelenskyy in saying the incursion was aimed at protecting its own citizens.

But it still remains unclear whether Ukraine will try to solidify control over the land it has captured or be forced to retreat.

Russian officials have warned that the incursion could expand. Authorities in the Belgorod region have said they are evacuating a district, and Putin, in his televised meeting, told the governor of a third border region — Bryansk — that it appeared “relatively calm” for now but “this doesn’t mean that the same situation will remain tomorrow.”

On Tuesday, a spokesperson for Russia’s emergencies ministry, Artyom Sharov, said more than 2,000 people had left or been evacuated from “borderline districts” in the Kursk region over the past 24 hours, state news agency Tass reported.