KYIV, Ukraine (AP) -- Russian troops and security forces fought for a second day Tuesday against an alleged cross-border raid that Moscow blamed on Ukrainian military saboteurs but which Kyiv portrayed as an uprising against the Kremlin by Russian partisans.
Vyacheslav Gladkov, governor of the Belgorod region on the Ukraine border, said forces continued to sweep the rural area around the town of Graivoron, where the alleged attack on Monday took place. Twelve civilians were wounded in the attack, he said, and an older woman died during the evacuation.
Gladkov urged residents of the area who evacuated to stay put and not come back to their homes just yet. "We will let you know immediately ... when it is safe," Gladkov said. "Security agencies are carrying out all the necessary actions. We're waiting for the counterterrorism operation to be over."
It was impossible to independently verify who was behind the attack or what its aims were. Disinformation has been one of the weapons of the almost 15-month war.
While it is not the first time Russia has alleged an incursion by Ukrainian saboteurs, it is the first time the operation to counter the raid has continued for a second day, highlighting the struggles Moscow is facing amid its bogged-down invasion of Ukraine and embarrassing the Kremlin. Russian territory and Russia-occupied areas of Ukraine have also been hit by drones and explosions that have derailed trains, though Kyiv officials brush off accusations of orchestrating them.
Ukraine said that Russian citizens belonging to murky groups calling themselves the Russian Volunteer Corps and the "Freedom of Russia" Legion were behind the assault.
Russian dissidents unhappy about Russian President Vladimir Putin's policies were behind the assault, Ukrainian Deputy Defense Minister Hanna Maliar said Tuesday.
"These are Russian patriots, as we understand it. People who actually rebelled against the Putin regime," she said.
The "Freedom of Russia" Legion in its Telegram channel on Tuesday claimed both groups were still operating in the Belgorod area and aimed to "liberate" the region.
Belgorod officials earlier this year said they had spent nearly 10 billion rubles ($125 million; 116 million euros) on fortifications to protect the region from an incursion amid the war.
Kremlin spokesman Dmitry Peskov said the raid "elicits deep concerns," and a "bigger effort" is required to prevent such raids in the future.
Peskov refused to say how many attackers were involved in the assault nor would he comment on why efforts to put down the attackers are taking so long. In a conference call with reporters Tuesday, he redirected those questions to Russia's Defense Ministry and Federal Security Service, or FSB.
The U.K. Defense Ministry said that Russian security forces "highly likely" are fighting partisans in at least three locations in Belgorod.
"Russia is facing an increasingly serious multi-domain security threat in its border regions, with losses of combat aircraft, improvised explosive device attacks on rail lines, and now direct partisan action," it said in a tweet on Tuesday.
Russia's Investigative Committee, the country's top law enforcement agency, announced an investigation into alleged terrorism and attempted murder in connection with the incident.
In addition to the alleged incursion, Gladkov reported multiple drone attacks on Graivoron and other settlements of the Belgorod region on Monday night. The attacks resulted in no casualties, but damaged buildings and caused a fire. On Tuesday morning, two more drones were shot down by the region's air defense systems.
Gladkov first reported on Monday afternoon that a Ukrainian Armed Forces saboteur group entered Graivoron, a town about five kilometers (three miles) from the border with Ukraine. The town also came under Ukrainian artillery fire, he said.
He later announced a counterterrorist operation in the area, and said that authorities were imposing special controls, including personal document checks, and stopping the work of companies that use "explosives, radioactive, chemically and biologically hazardous substances."
The Russian Volunteer Corps claimed to have breached the border in early March. The shadowy group describes itself as "a volunteer formation fighting on Ukraine's side." Little is known about the group, and it's not clear if it has any ties with the Ukrainian military. The same is true for the "Freedom of Russia" Legion.
The Belgorod region in southwest Russia, just like its neighboring Bryansk region and several other areas, has witnessed sporadic spillover from the war, with its border towns and villages regularly coming under shelling and drone attacks.
Elsewhere, Ukrainian forces have made minor progress against Russian forces on the edge of Bakhmut, the eastern Ukrainian city that Moscow claims to have captured, according to Maliar, the Ukrainian deputy defense minister.
She said Tuesday that Ukrainian troops still control the southwestern outskirts of the city and that fighting continues in the suburbs, on Russia's flanks.
Ukrainian military leaders say the fight in Bakhmut isn't over.