In the hours after the U.S.
and Israel began striking Iran on Saturday, a message was broadcast to ships in a critical waterway.
The saying that the Strait of Hormuz is closed?
and basically warning that the vessels not go through.
Roughly a fifth of the world's oil supply moves through the Strait of Hormuz on a normal day.
It's the main way Saudi Arabia, Kuwait, Iraq, the UAE and Iran get oil out to the rest of the world.
Here's our colleague Rebecca Fung.
That was like the initial warning, seemingly from Iran not to enter the strait.
And what was your initial reaction when you heard the warning?
Very, very bad.
That was my reaction.
Because closing it is like the doomsday scenario.
So my first reaction was like, oh no, here we go.
After ships were banned from moving through the strait,
much of the world's oil supply became stuck around the Persian Gulf.
Since the conflict began over the weekend, oil prices have jumped.
Yeah, it's very dramatic.
Oil and gas prices spiked today.
US oil traded 7.6% higher at $72.12 per barrel,
while international standard Brent was up 8.6% at $79.11 per barrel.