(Bloomberg) — Aluminum jumped the most in three weeks along with other industrial metals as signs that a US-Iran ceasefire still holds reduced fears of a full-blown war that may drag down economic growth.

The lightweight metal rose as much as 2.1%, the biggest intraday increase since April 13, while other risk assets including US equities also gained. The US played down the prospect of a return to active war with Iran after a day of clashes involving ships in the Strait of Hormuz and missile strikes against the United Arab Emirates.

Attacks by Tehran on vessels in the Persian Gulf and the UAE didn’t constitute a breach of a ceasefire, General Dan Caine, the chairman of the Joint Chiefs of Staff, told reporters at the Pentagon on Tuesday. Speaking alongside him, Defense Secretary Pete Hegseth confirmed the truce that began just under a month ago is still in place. 

Aluminum prices were also supported by supply tightness in the physical market as the effective halt of the Strait of Hormuz disrupted metal shipments out of the region, which accounts for nearly 10% of global supply. Iranian drone and missile strikes on two of the largest smelters there in late March further worsened the supply outlook as it takes time to fully restart the plants.

Prices of the lightweight metal have gained 14% since the war broke out in late February. 

Aluminum climbed 1.7% to $3,582.00 a ton on the London Metal Exchange as of 12:05 p.m. New York time. Copper gained 1% and zinc rose 0.7%. 

–With assistance from Jack Ryan and Katharine Gemmell.

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