WASHINGTON — U.S. intelligence officials warned American defense companies on Thursday to increase security precautions following several acts of sabotage in Europe that officials have blamed on Russia.

The public bulletin issued by the National Counterintelligence and Security Center advised companies involved in defense work — particularly those providing support to Ukraine in its war against Russia — to step up their defenses in the face of Russia’s escalating aggression toward Ukraine’s allies.

“Russia’s sabotage activities in Europe increase the risk to U.S. companies abroad and potentially at home,” the officials wrote in the warning. “Such sabotage operations can sow fear and doubt, damage important infrastructure, disrupt commerce, or cause injury and death.”

U.S. and European intelligence officials have said Russia perpetrated several recent acts of sabotage targeting European defense companies, logistics facilities, public utilities and military installations. Often, the officials said, Russian intelligence has hired local criminals to carry out the acts, which include arson attacks in the United Kingdom and Poland.

Earlier this month, security officials blamed Russia for a plot to smuggle incendiary devices onto cargo planes headed to North America, including one that caught fire at a courier hub in Germany and another that ignited in a warehouse in England.

Along with disinformation and propaganda, it’s part of a larger hybrid effort to undermine the ability of Ukraine’s allies to support its defense against Russia’s invasion.

Russia has denied the allegations. A message left with Russia’s embassy in Washington was not immediately returned Thursday.

The National Counterintelligence and Security Center is an agency within the Office of the Director of National Intelligence, focused on protecting national assets from intelligence threats. Thursday’s bulletin was jointly issued by the FBI and several Department of Defense agencies.