The Trump administration is hitting Russia with new sanctions punishing President Vladimir Putin’s government for using a chemical weapon against an ex-spy in Britain, US officials told NBC News Wednesday.

Secretary of State Mike Pompeo has signed off on a determination that Russia violated international law by poisoning Sergei Skripal and his daughter in March, the officials said.

Although the US joined European countries in publicly blaming Moscow within days of the attack, Trump’s administration had never issued the formal determination that triggers automatic sanctions under a decades-old US law on chemical weapons.

The decision could bolster President Donald Trump’s claim that despite the noise of the Mueller probe that he calls a “witch hunt,” his administration has been tough on Moscow in practice and has hit hard when needed.

But Trump had to be nudged by Congress into unleashing the penalties after blowing more than a month past a statutory deadline.