TALLINN, Estonia — Estonian authorities said Tuesday that an arson attack carried out last month on a defense company that provides military vehicles to Ukraine was an act of sabotage commissioned by Russian security services.

Foreign Minister Margus Tsahkna said that “such actions are absolutely unacceptable” and that Russia’s charge d’affaires in Tallinn was being summoned to his ministry.

A fire broke out overnight on Aug. 15 at a building in the Estonian capital used by Milrem Robotics, but was quickly brought under control, the BNS news agency reported. On Aug. 17, two Latvian suspects were detained in neighboring Latvia, and a third followed the next day. The suspects were handed over to Estonia.

Milrem has supplied THeMIS unmanned ground vehicles to Ukraine.

The Estonian Internal Security Service said that it has concluded that the arson attack “was a deliberate and pre-planned act commissioned by Russian security services.”

It said in a statement that “the modus operandi of the Milrem attack is consistent with other acts of sabotage carried out in Europe on behalf of Russia,” adding that it “assesses that the attack is directly attributable to the Russian Federation.”

Kremlin spokesman Dmitry Peskov said that “such statements are unfounded, ill-considered, absolutely not reflecting the reality, not containing any substantiation whatsoever.”

“We cannot take such statements seriously, and we won’t,” Peskov said.

Moscow has been widely accused by Western officials of running a campaign of sabotage and disruption with the aim of undermining support for Ukraine and destabilizing European nations.

The Associated Press has tracked around 200 incidents of sabotage and malign activity across Europe blamed on Russia since the full-scale invasion of Ukraine on Feb. 24, 2022.

That includes organizing plots to set fire to warehouses, launching drones and trying to kill enemies abroad as well as stealing defense technology and carrying out cyberattacks on critical European infrastructure.

In a recent case that pointed to an escalation of such activity, Germany blamed Russia for an attempted attack at Leipzig/Halle Airport in early August using a drone laden with explosives.

Estonian Prime Minister Kristen Michal wrote on X that “we will not be intimidated.”