Explosions struck the building housing the security services of the breakaway Moldovan republic of Transnistria on Monday, days after Moscow said the Russian-backed region could be drawn into the war in Ukraine.

Transnistria, which is controlled by pro-Russian separatists and hosts Russian troop bases and arms depots, borders western Ukraine. It is seen as a potential flashpoint in rising tensions between Moscow and the west that have soared since President Vladimir Putin’s invasion of Ukraine two months ago.

A senior Russian commander said last week that the Russian army’s move to capture southern Ukraine would open “another way to Transnistria”. Moscow has claimed “there are also instances of oppressing the Russian-speaking population” in Transnistria, an argument that was used to justify the invasion of Ukraine.

The explosions inside the building hosting Transnistria’s state security ministry in Tiraspol were caused by a rocket-propelled-grenade attack, the region’s authorities said.

Photographs shared by the Transnistrian authorities appeared to show a rocket-propelled-grenade launcher left on the road outside the building. No details of who may have carried out the attack were provided.

“[There are] broken windows on upper floors. Smoke billows from the rooms,” Transnistria’s government said in a statement. “An investigative team, sappers, firefighters, ambulance doctors and specialists from other emergency services are on site,” it said, noting that no casualties had been reported.

Moldova’s government in Chisinau said in a statement that it was “concerned about the incident” and “called for calm” in the region. “The aim of today’s incident is to create pretexts for straining the security situation in the Transnistrian region, which is not controlled by the constitutional authorities,” it added.

Transnistria separatists, backed by Moscow, fought a war against newly independent Moldova in 1992, and a ceasefire led to the region seceding de facto from Chisinau. The region, which is separated from the rest of Moldova by the Dniester river, is internationally recognised as a part of Moldova.

Moldova, a former Soviet state contested between pro-western and pro-Russian political groups since the Soviet Union collapsed, has called for help from western countries to help it weather the effects of the war in Ukraine and maintain “stability”.

“We are the single most fragile neighbour of Ukraine . . . we need help to stay on our feet,” Nicu Popescu, the foreign minister, told the Financial Times last month. “The war is a major problem for Moldova . . . It is in no one’s interest to see Moldova not be able to maintain its current political and socio-economic stability. And the risks are quite high.”

Russia’s foreign ministry said on Monday that it did not see any risks of escalation of the situation in Transnistria.