Oil crude prices surged around 5% Monday after Israel and Iran exchanged strikes, testing a fragile truce and threatening hopes for a deal to end the Middle East crisis.

The contract for August jumped 5.1% to $97.83 a barrel, while West Texas Intermediate (WTI) climbed 4.8% to hit $94.85.

Israel said on Monday it hit a petrochemical plant in Iran's southwest, along with strikes elsewhere ​on military targets. That's despite U.S. President Donald Trump reportedly telling Israeli Prime Minister Benjamin Netanyahu to refrain from ​further attacks.

In the first hit on an energy site inside Iran since the April 8 cease-fire, Israel ⁠said it struck targets at the Mahshahr petrochemical complex. A provincial official told Iran's semi-official Fars news agency that parts of the ​plant were damaged.

Hopes are now eroding for an imminent end to the wider war and a restart to crude flows through the ​Strait of Hormuz, through which roughly a fifth of the world’s oil and liquefied natural gas (LNG) used to transit.

Monday's gains erased Friday's losses, when prices fell on hopes of a de-escalation in the U.S.-Iran conflict. Oil prices have climbed just under 60% since the start of the war in ​late February, but remain below highs marked in March when Brent reached nearly $120 per barrel.

On Sunday, Iran fired a salvo of missiles ​at Israeli targets in retaliation for the strikes on Lebanon. Even so, Trump insisted that an agreement to end the wider ‌war ⁠remains well within reach.

Iran has made a cease-fire with Lebanon a condition for a peace deal with Washington.