US Secretary of State Antony Blinken on Monday called on the United Nations to hold Iran accountable for a fatal drone strike last month in the Arabian Sea, warning that failure to do so would "fuel their sense of impunity."

“We are confident that Iran conducted this unjustified attack, which is part of a pattern of attacks and other provocative behavior,” Blinken said during a virtual UN Security Council session on maritime security.  

Last week, the United States and the rest of the Group of Seven leading industrial nations said all evidence suggests that Iran was behind the drone strike on the Mercer Street tanker, which was en route to the United Arab Emirates from Tanzania when it came under attack July 29. Israel has also blamed its archrival Iran for the strike on the Liberian-flagged vessel, which is managed by a London-based company owned by Israeli billionaire Eyal Ofer.

A US military investigation concluded last week that Iranian-produced drones struck the Mercer Street. US Central Command said Friday that the components of the drones examined by US Navy explosive experts were “nearly identical” to previously recovered Iranian models. Chemical tests revealed a nitrate-based explosive was used in the attack, “indicating the [unmanned aerial vehicle] had been rigged to cause injury and destruction," CENTCOM said.