KYIV, Ukraine — Russian forces foiled another attempted cross-border incursion by Ukraine into southwestern Russia, a local official said Sunday, months after Kiev staged an audacious attack on its nuclear-armed foe that Moscow still they struggle to stop him.

An “armed group” tried to breach the border between Ukraine and Russia’s Bryansk region on Sunday, its governor, Aleksandr Bogomaz, said, but was beaten back. Bogomaz did not clarify whether Ukrainian soldiers carried out the alleged attack, but claimed late Sunday that the situation was “stable and under control” by the Russian military.

There was no immediate acknowledgment or response from Ukrainian officials.

The region borders Kursk province, where Ukraine launched a surprise push on August 6 that shook the Kremlin and was Russia’s biggest attack since World War II. Hundreds of Russian prisoners were blindfolded and trucked away in the first moments of the lightning advance, and battle-reinforced Ukrainian units quickly advanced across hundreds of square miles (square kilometers) of territory.

Responsibility for previous incursions into Russia’s Belgorod and Bryansk regions has been claimed by two troubled groups: the Russian Volunteer Corps and the Russian Freedom Legion.

Russian officials and state media have tried to play down the significance of Kiev’s breakthrough in Kursk, but the country’s forces have so far failed to drive Ukrainian troops out of the province. Western officials have speculated that Moscow could send troops from North Korea to step up its efforts to do so, igniting the nearly three-year-old war and bringing geopolitical consequences as far as the Indo-Pacific region.

Russian lawmakers on Thursday ratified a pact with Pyongyang providing for mutual military assistance, a move that comes as the US confirmed the deployment of 3,000 North Korean troops to Russia.

North Korean units were detected in Kursk on Wednesday, according to Ukraine’s Main Intelligence Directorate, known by its acronym GUR. The soldiers underwent several weeks of training at bases in eastern Russia and were equipped with clothes for the coming winter, GUR said in a statement late Thursday. He provided no evidence for his claims.