The White House condemned the poisoning of Russian opposition leader Alexei Navalny on Wednesday. 

The German government earlier in the day announced that Navalny had been poisoned with a chemical nerve agent called Novichok. The announcement came after the news that the Kremlin critic had fallen ill last month and was taken to a Berlin hospital for treatment. 

A spokesman for the National Security Council (NSC) called the findings "completely reprehensible." 

"The United States is deeply troubled by the results released today. Alexei Navalny’s poisoning is completely reprehensible," spokesman John Ullyot said in a statement. "Russia has used the chemical nerve agent Novichok in the past."

The U.S. will "work with allies and the international community to hold those in Russia accountable, wherever the evidence leads, and restrict funds for their malign activities," Ullyot said, adding that the Russian people should be able to express their views without fear of retribution.

Other world leaders also spoke out against Russia after the German government determined that a chemical nerve agent was used to poison Navalny.

"They wanted to silence him and I condemn this in the strongest possible terms, also on behalf of the entire Federal Government," German Chancellor Angela Merkel said.

"It’s outrageous that a chemical weapon was used against Alexey Navalny," British Prime Minister Boris Johnson tweeted. "We have seen first-hand the deadly consequences of Novichok in the UK. The Russian government must now explain what happened to Mr Navalny – we will work with international partners to ensure justice is done."

Navalny is a noted critic of Putin and an anti-corruption activist.

The Kremlin drew international outrage two years ago when it was accused of poisoning Russian double agent Sergei Skripal and his daughter Yulia in the English town of Salisbury. Officials determined Novichok was involved in that attack.