Ukraine and Russia-backed separatists in an eastern district of Luhansk are trading accusations of fighting escalation after the US claimed that Moscow is looking for a pretext to invade.

On Thursday, the Ukrainian military’s eastern command center claimed that Russian-backed forces fired heavy artillery at the village of Stanytsia-Luhanska “with special cynicism.”

“The shells hit a kindergarten,” it said, adding that two civilians had been injured and public infrastructure had been damaged. Electricity was also cut off in some areas of the village.

Civilians were seen hiding in a cellar and a kindergarten playroom, with rubble strewn on the floor and a shell hole in the wall, according to photos posted on the command center’s Facebook page.

Ukraine’s President, Volodymyr Zelenskyy, called the pro-Russian forces’ shelling of the kindergarten a “major provocation.”

The Kremlin, for its part, said it was “seriously concerned” about reports of an escalation after separatists accused government forces of opening fire on their territory four times in the previous 24 hours.

“Reports of alleged abnormal military activity by Ukraine in Donbass are a blatant attempt by the Russian government to fabricate pretexts for invasion,” British Foreign Secretary Liz Truss tweeted. This is straight from the Kremlin’s playbook.”

Dmytro Kuleba, Ukraine’s Foreign Minister, did not mention any injuries but condemned the alleged shelling.

“We call on all partners to swiftly condemn Russia’s grave violation of the Minsk agreements amid an already tense security situation,” he said, referring to a 2014 international agreement meant to end the war.

Former US ambassador to NATO Kurt Volker stated that NATO’s concerns about an alleged pretext operation should be taken “absolutely” seriously.

“Russia has consistently done this during its eight-year occupation of parts of Donbas.” It claims that Ukraine has fired on its troops whenever it wants to raise tensions or put pressure on Ukraine. It’s something Russia does on a regular basis. That is clearly happening now,” Volker told Al Jazeera.

Meanwhile, Russian news agencies reported that separatist forces in Luhansk claimed the Ukrainian military escalated fighting. “The situation on the line of contact has deteriorated significantly over the last 24 hours,” Yan Leshchenko, head of the People’s Militia in the self-proclaimed Luhansk republic, told reporters.

“The enemy is attempting to escalate the conflict on the direct orders of Kyiv’s military-political leadership.”

The allegation of a Ukrainian escalation was described as “disturbing” by Kremlin spokesman Dmitry Peskov in Moscow.

“This is a source of great concern,” he said. “We hope that our adversaries in Western capitals, including Washington and NATO, will use all of their influence to warn Kyiv authorities against further escalation.”

According to Al Jazeera’s Andrew Simmons, reporting from Kyiv, firing mortars, grenade launchers, and machineguns is a violation of the Minsk Protocol, an agreement that sought to end the war in the Donbas region.

According to Simmons, the Ukrainian government reported 34 incidents of violence in various cities on Thursday.

While border clashes are common, tensions are high as Ukraine and its Western allies claim Russia has deployed a massive invasion force. The US intelligence community has accused Moscow of attempting to create a pretext by fabricating an atrocity.

NATO claims that more than 100,000 Russian troops are stationed on the border, but Moscow insists that it is seeking a diplomatic solution to its security concerns and to reduce the West’s influence in Eastern Europe.