The United States Secret Service says it is on high alert after former FBI director James Comey posted a cryptic ‘8647’ code on social media, interpreted by many as calling for the assassination of President Donald Trump.

In a now-deleted post on Instagram, Mr Comey had on Thursday posted a photo of an arrangement of seashells on a sandy beach to spell out ‘8647’ along with the caption “cool shell formation on my beachwalk”.

The code ‘86’ translates to eight feet wide and six feet deep, the standard measurement of a grave, is a slang that has long been used to describe placing a hit on someone, and the ’47’ was construed to mean the 47th president, which is the official designation of Mr Trump.

The post quickly went viral and generated widespread condemnation from top officials within the Trump administration and Republican politicians, forcing Mr Comey to delete the post and later issuing a clarification, stating he was unaware of the meaning of the numbers.

“I posted earlier a picture of some shells I saw today on a beach walk, which I assumed were a political message,” Mr Comey posted on Instagram. “I didn’t realise 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.” 

Meanwhile, Department of Homeland Security Secretary Kristi Noem said in a statement on X that the agency and the Secret Service were aware of the post made by Mr Comey, adding that an investigation has been opened.

“Disgraced former FBI Director James Comey just called for the assassination of @POTUS Trump. DHS and Secret Service are investigating this threat and will respond appropriately,” Ms Noem posted. 

Similarly, FBI director Kash Patel also issued a statement that “we are aware of the recent social media post by former FBI Director James Comey, directed at President Trump”. 

Mr Patel said, “We are in communication with the Secret Service and Director Curran.”

Mr Comey was appointed by former President Barack Obama as the seventh director of the FBI in 2013 and remained in the position until Mr Trump sacked him during his first term in office in 2017.