Oil prices surged more than 2% on Monday after a fresh exchange of US and Iranian attacks around the Strait of Hormuz renewed the risk of disruption to crude shipments through the key oil chokepoint.

Brent crude futures climbed $2.33 to $90.15 a barrel, while US West Texas Intermediate crude rose $1.99 to $85.06.

The gains came after US forces struck Iranian rocket launchers on Larak Island in the Strait of Hormuz on Sunday, prompting Iran to retaliate against US forces in the region. The latest escalation marks the first direct US-Iran military exchange in several weeks and comes as the Middle East conflict enters its sixth month.

The renewed fighting has put the focus squarely back on the Strait of Hormuz, through which roughly one-fifth of global oil supplies flowed before the conflict. Shipping through the waterway has already been sharply reduced as operators remain wary of attacks on vessels and the unresolved confrontation between Washington and Tehran.

The number of visible commodity vessels passing through the strait over the weekend fell to just five a day, according to shipping data, highlighting the caution among shipowners. A tanker was also struck by a projectile while sailing through the waterway on Saturday, although no casualties were reported.

The latest price jump reverses some of the sharp losses recorded last week, when Brent fell more than 5%.