Copper fell after the US and Iran exchanged fire in the Persian Gulf on Monday, casting doubt over the fate of a ceasefire and raising concerns about further escalation in the conflict that’s upended global markets.

The metal dropped as much as 1.7% on the London Metal Exchange after closing higher for the first time in seven sessions on Friday. The LME was shut Monday for a UK public holiday. The American military fought off Iranian attacks as it facilitated the passage of two US-flagged vessels through the Strait of Hormuz, while a drone strike hit Fujairah port in the United Arab Emirates.