Oil surged to almost $87 a barrel, its highest level in a month after the United States and Iran traded attacks as they vied over the Hormuz Strait.

The U.S. and Iran disputed whether Hormuz was open to ship traffic after trading strikes over the weekend.

Brent crude climbed above $78 and WTI gained over 3% as escalating Iran-US tensions and threats to Strait of Hormuz shipping raised global supply concerns.