Oil prices held firm ​on Thursday after Brent ​crude breached $100 a barrel, with traders ​bracing for deeper supply disruption as Iran and the United States launched their largest attacks on shipping since their ‌six-month-old conflict ⁠began.

Brent ⁠crude futures rose 0.1% to $101.34 a barrel by 0107 ​GMT. U.S. West Texas Intermediate crude was at $96.55 a barrel, up ​0.5%.

Iran said on Wednesday it had attacked 10 ships near the Strait of Hormuz after the ​U.S. sank five Iranian oil ⁠tankers, and ‌Iran's Revolutionary Guard Corps said ​it would ​escalate its response to any further ⁠attacks.

"The tit-for-tat attacks suggest oil flows from ​the Persian Gulf are likely to remain ​disrupted for the foreseeable future," ANZ analyst Daniel Hynes said in a client note.

Oil flow through the Strait of Hormuz, the waterway that before the war carried roughly a fifth of ‌global oil and gas supplies, remains well below its pre-war level.

The U.S. Energy ​Information Administration ​on Wednesday ⁠raised its oil price forecasts for this year and next, as global stockpiles drop due to the loss ​of Middle Eastern supply.

"The broadening of the conflict threatens to risk even deeper disruption to oil supplies that had already left the oil market scrambling to adjust," Hynes said.