Germany's government says it's "fairly likely" that Russian opposition leader Alexey Navalny was poisoned.
A spokesperson for Chancellor Angela Merkel said Monday he'll need special protection due to the suspected poisoning.
The 44-year-old said he felt sick on a flight back to Moscow last week, prompting the plane to make an emergency landing. He was airlifted to a Berlin hospital over the weekend in "stable condition."
Navalny was hospitalized last year for another suspected poisoning, but doctors said it was an allergic attack.
Navalny is a fierce critic of Russian President Vladimir Putin.
In past years, several other Russian opposition figures have become sick by suspected poisonings.