The Islamic Republic has vowed to block the region’s oil exports, saying it would not allow “even a single liter” to be shipped to its enemies.

At least 12 incidents have been confirmed involving vessels in and around the Strait of Hormuz since the war began, according to two global trackers.

The Strait of Hormuz is the narrow mouth of the Persian Gulf through which about a fifth of the world's oil passes. Tankers traveling through the strait, which is bordered in the north by Iran, carry oil and gas from Saudi Arabia, Kuwait, Iraq, Qatar, Bahrain, the UAE and Iran. Most of that oil goes to Asia.

Iran conflict halts Strait of Hormuz tanker traffic, risking global oil supply. Here’s why the narrow Gulf passage is vital and how it impacts crude prices.

The Strait of Hormuz is the narrow mouth of the Persian Gulf through which about a fifth of the world's oil passes.

Despite efforts by the U.S. and others to address the crisis, the vital Strait of Hormuz, through which 20 percent of the world’s oil supply is moved, remains effectively closed. The war continues to have a dramatic impact on the shipping and oil industry,

Gas prices are climbing as the Iran war essentially shuts down shipping through the Strait of Hormuz, a narrow passage off Iran’s coast that serves as a key route for oil and gas from the Persian Gulf.

Follow live NBC News coverage and latest updates on the Iran war, as Tehran attacks ships around the Strait of Hormuz, the price of oil spikes and Israel strikes Lebanon.