Donald Trump claimed James Comey "knew exactly what that meant" when he posted a picture on social media showing seashells on a beach arranged to resemble the numbers 8647.
The US president has claimed that the former FBI director's post called for his assassination.
According to the dictionary site Merriam-Webster, “86” means to "to throw out,” or “get rid of,” and derives from a 1930s slang term for “sold out.” The number 47 is believed to refer to Mr Trump, as the 47th president.
Mr Comey said he did not know what the numbers meant.
"I didn’t realize some folks associate those numbers with violence. It never occurred to me, but I oppose violence of any kind, so I took the post down," he said.
