Russia has hit back at the U.S. for slapping new sanctions on Russians accused of election meddling by adding more Americans to its “black list,” its foreign minister said. “From the very beginning, we use the principle of parity on the number of people included in sanction lists. So we will expand our ‘black list’ with another group of Americans,” Sergei Ryabkov said Friday. Although Ryabkov didn’t specify the number of Americans added to the black list, the U.S. sanctions implicated 19 Russians, which the retaliatory sanctions are expected to match. Reuters reported Ryabkov didn’t rule out making further sanctions against the U.S. in response what is considered to be the strongest action by the Trump administration against Russia so far. “Those politicians are playing with fire by destroying Russian-American relationship because simultaneously they shake global stability,” Ryabkov added.