Russian President Vladimir Putin threatened to retaliate for the seizure of commercial vessels from Western countries, calling such actions "piracy."
One such case took place in June when the French Navy, with support from the UK, intercepted an oil tanker under international sanctions that was heading to Moscow.
"It is unacceptable that boats skirt international sanctions, violate the law of the sea and finance the war that Russia has been waging for more than 4 years against Ukraine," French President Emmanuel Macron said back then when announcing the decision.
Putin called the seizures "nothing but piracy and robbery," adding that "if this is done, we will be forced to respond in kind."
He went on to say that Moscow's potential response may not take place with in the same waters where Russian vessels were seized, but in "any area where we see it as necessary and appropriate."
The warning comes as NATO countries believe Russia could escalate hostilities in the future.
Reuters detailed that Lithuania, Poland, Latvia and Estonia have made claims of such nature. The former said Moscow is considering the stage attack and the other three warned of acts of sabotage.
"We are not naive, we see the information, we read between the lines and we are doing our homework," Lithuanian Defence Minister Robertas Kaunas told the outlet.
"We are increasing the security of our critical infrastructure, we constantly exchange information with our intelligence on what to do next," he added.
The outlet went on to note that Lithuania sent a military unit to back up riot police and secure its liquefied natural gas import terminal, one for oil products, a key power link with Poland and a hydro plant. "We are clearly signaling that, if needed, we will be defending ourselves", Kaunas said.
Another recent report claimed that Russian President Vladimir Putin is considering a limited assault on a NATO country to test the alliance.
The assessment from U.S. intelligence officials claimed such a scenario could take place in the next few years, with another possibility being a cyberattack.
The Wall Street Journal detailed last week that previous assessments believed that Putin wouldn't make such a decision while still fighting in Ukraine, but the thinking changed earlier this year as the war continues and Kyiv manages to strike deep into Russian territory and inflict damage on its oil industry while keeping the front lines largely unchanged.
The goal of attacking a NATO country, the report added, would be fracturing the transatlantic alliance. Such an attack could take place between this fall and 2029. The likelihood of it happening is low but grows as time goes by and Putin does not manage to make strategic gains in the war.
