Following a surprise cross-border offensive that began on August 6, Ukrainian forces had advanced about 35 kilometers (21 miles) into Russian territory in the Kursk region as of August 9, according to an assessment by the US-based Institute for the Study of War (ISW).

Russia has been quick to bolster its defenses. The Russian military has said it will send more troops and armored vehicles to repel the biggest attack on Russian territory since the war with Ukraine began 30 months ago.

Russian television broadcast images of convoys of military trucks carrying artillery, heavy machine guns and tanks. Early on August 10, Russian news agencies reported that the National Anti-Terrorist Committee had launched an “anti-terrorist operation” in the Kursk region and the neighboring Bryansk and Belgorod regions.

Under Russian law, security forces and the military are given full powers to impose a state of emergency during “anti-terrorist” operations. For example, travel can be restricted, vehicles can be confiscated, phone calls can be monitored, areas can be declared no-go zones, checkpoints can be set up, and security can be increased at key infrastructure sites.

The Ukrainian incursion has clearly introduced an unpredictable new element into a war that is already moving slowly on multiple fronts. But military analysts have questioned whether the operation is worth the risk, given that Ukrainian forces are already stretched.

Ukrainian leaders have so far remained silent, refusing to publicly acknowledge launching a cross-border attack, while the United States – Kiev’s closest ally – said it had not been informed of the plan in advance.

Main question

The fighting in Russia showed no signs of abating on August 9, when the Ukrainian military said it had attacked a Russian airport in the Lipetsk region, bordering Kursk, hitting warehouses storing guided air bombs.

A major drone attack has caused several explosions and a fire at a military airport, local authorities in Russia say.

Military analysts said the cross-border offensive involved at least four brigades, supported by artillery, air defense and electronic warfare, leading to rapid advances on land.

“It looks like there are about four to five Ukrainian brigades, so I would estimate there are 10,000 to 12,000 Ukrainian soldiers and others involved,” said Dara Massicot, who previously worked at the Pentagon as an analyst on Russian military capabilities.

“It looks like a well-planned and coordinated combined arms operation,” said Franz-Stefan Gady, a Vienna-based military analyst.

The key question now, Mr. Gady, Ms. Massicot and other experts say, is whether Ukraine can maintain the momentum and turn its success on Russian territory into useful gains.

The Ukrainian military has few reserves to throw into the fight, analysts say, and continues to suffer from shortages of weapons and ammunition. It is also unclear what Ukraine ultimately hopes to achieve.

A senior Ukrainian official, speaking on condition of anonymity to discuss the operation, said the goal was to draw Russian troops away from other areas of the front line where Ukrainian units were struggling. Russia would likely respond with noncombatant reservists in Ukraine, military experts said.

Probe

“There are a few different explanations. It could be an attempt by Ukraine to block some of the rail and road networks coming from northern Russia to bring troops and equipment down – threatening the Kharkiv region,” said Ms Massicot, concluding that it was too early to say anything as the operation was still in its early stages.

One goal could be to boost morale among the Ukrainian people, said Mick Ryan, a retired major general of the Australian Army and a fellow at the Lowy Institute.

“With eight months of defensive operations, continued airstrikes on infrastructure and ongoing power shortages, the will of the people will be at the forefront of the Ukrainian government ’s considerations about the trajectory of the war,” Ryan said.

Notably, Ukrainian troops have entered Sudzha, a small town of about 6,000 people located 6 miles (9.6 km) from the Ukraine-Russia border. On August 9, the Ukrainian military claimed in a video that the town was under its control. The claim could not be independently verified.

Ukrainian video reportedly shows their forces taking control of a gas metering station operated by Russia's Gazprom company in the town of Sudzha.

"The town is controlled by the Ukrainian armed forces, the town is very quiet, all the buildings are intact," a soldier in the video said, adding that the "Gazprom strategic facility" was under the control of a Ukrainian battalion.

The last transit point for Russian gas to Europe via Ukraine is near the small town of Sudzha. So far, the gas has continued to flow uninterrupted. However, the importance of Russian gas to Europe has decreased since Russia launched a special military operation in Ukraine in February 2022.

Emil Kastehelmi, an analyst with the Black Bird Group, a Finland-based organization that analyzes battlefield imagery, said on social media that some Ukrainian units appeared to be conducting raids further north toward Lgov, a town about 50 miles (80 km) from the border, in what appeared to be a move to probe Russian defenses.

Minh Duc (According to NY Times, DW, France24, NPR)