European allies' findings that Putin critic Alexei Navalny was killed with a rare toxin from poison dart frogs is "troubling," said Secretary of State Marco Rubio on Sunday, adding the U.S. is "not disputing" the report.
The big picture: Rubio told reporters in Bratislava during a visit to Slovakia "we don't have any reason to question" the report that the U.K., France, Germany, Sweden and the Netherlands issued Saturday, which the Kremlin disputes.
