"The suspect, who allegedly sent a letter with the deadly poison ricin to the White House, was detained while attempting to enter the United States from Canada," the report said.
Information about the detainee is not provided.
Earlier, the FBI and the US Secret Service began an investigation into the receipt of a suspicious package, which, according to media reports, was sent to American leader Donald Trump.
According to CNN, law enforcement agencies intercepted a package with ricin poison addressed to Trump.