MOSCOW — Russian President Vladimir Putin called a special meeting of the National Security Council on Thursday, following reports from his own intelligence service about fighting with Ukrainian units on Russian territory.

A planned trip to the Caucasus on Friday was canceled on short notice.

The topic of the Security Council meeting is unknown, but there has long been speculation that Russia could officially declare war on Ukraine and order a further mobilization of hundreds of thousands of troops for the army.

Kremlin spokesman Dmitry Peskov, when asked by journalists whether the gathering of senior defense officials would upgrade what Moscow continues to call a “special military operation,” said: “I don’t know, I can’t say.”

It is a punishable offense in Russia to refer to Moscow’s offensive in Ukraine as a war.

Another outcome of the meeting could be greater restrictions on civil rights and steps towards a war and command economy.

Former Russian president Dmitry Medvedev — now the deputy chair of the Security Council — warned NATO on Thursday against making fighter jets available to Ukraine and maintaining them in Poland, saying that doing so would be tantamount to directly going to war against Russia.

“And anyone who decides on the delivery (repair) of such equipment or means of destruction, as well as foreign mercenaries and military trainers, would have to be considered a legitimate military target,” he wrote on Telegram.

Medvedev was seen as fairly liberal during his time as prime minister and president. He is now presenting himself as a hardliner in the context of the war, with observers suggesting that he is seeking to secure his position in the Russian power structure.

Putin accused Ukraine of terror earlier in the day, after reports of fighting in the south-western Russian border region of Bryansk.

It was “another terrorist attack and another crime,” the Russian president said during a video conference.

Russia started the war against Ukraine when it invaded its neighbor, in an unprovoked attack, on February 24, 2022.

The domestic intelligence service FSB spoke of heavy fighting with “Ukrainian nationalists” in Bryansk. Kyiv has denied responsibility for the incidents, saying it came from targeted Russian disinformation.

According to Russian sources, a motorist was killed and a 10-year-old child was injured in the Bryansk region by shelling from what the Russians called Ukrainian sabotage forces. The Russian sources said the child was being cared for in hospital.

“They entered the border area where they opened fire on civilians. They saw that it was a civilian vehicle, that there were civilians and children inside,” Putin said.

Media have also circulated reports of an alleged hostage situation and a firing on a school bus, but these were then retracted even by officials in Russia and rejected by Ukrainian authorities, who noted that remote learning has been in place for several months.

The administration of the Sushany area also denied that several people had been taken hostage there by Ukrainian militants.

Putin blamed the shooting on the leadership in Kyiv, which he once again portrayed as alleged “neo-Nazis.” Ukrainian President Volodymyr Zelenskyy is Jewish.

Putin claimed Ukraine was trying to rob Russia of its historical identity and language by force.

“But I repeat myself: They will not succeed, and we will crush them.”

As for the alleged attacks, Russian nationalists later claimed responsibility for them in a video. While some Russian nationalists support Putin’s war, others are fighting on Kyiv’s side. However, it is unclear whether the action in Bryansk was coordinated with the Ukrainian military.

Since shortly after the start of the war, Russia has repeatedly complained about shelling on its own territory. However, the number of casualties and damage in Russia are completely out of proportion to the consequences of the war in Ukraine, where many cities have been destroyed and thousands killed.

In Ukraine, meanwhile, defensive units repulsed several Russian attacks on the eastern town of Bakhmut on Thursday, according to the military command in Kyiv.

Russian artillery shelled a number of smaller localities around Bakhmut, the general staff in Kyiv said in its situation report.

Russian troops are pressing the city from three sides and have been trying to completely encircle Bakhmut for weeks.

On the front lines in the south near Kherson and Zaporizhzhya, repeated Russian artillery attacks have caused concern. The Ukrainian military registered attempts by Russian reconnaissance teams at several points to scout possible starting points for later attacks.

Zelenskyy vowed retaliation for an overnight Russian missile attack on the city of Zaporizhzhya that hit a multistory residential building, killing at least two.

“We will respond militarily and legally to today’s brutal Russian missile attack on Zaporizhzhya,” Zelenskyy said in his evening video address. “The occupier will inevitably feel our strength, the strength of justice in the truest sense of the word.”

Ten residents of the apartment building were still missing on Thursday evening, according to official information.