Rising oil prices just passed another milestone, jumping above $70 per barrel in Monday morning trade in Asia.
Oil prices have been climbing partly because of expectations that President Donald Trump will abandon the 2015 Iran nuclear deal, which allowed Iran to export more crude.
This is the first time the US crude benchmark has been above $70 since November 2014.
"The focus of oil markets is currently on the US president's pending decision on the fate of the Iran nuclear deal," said Victor Shum, an oil industry analyst at research firm IHS Markit.
The recent surge in prices suggests markets are assuming there will be some disruption to Iran's exports, Shum said. Trump has to decide by May 12 whether to bring back sanctions against the country.
US oil prices have gained more than 16% since the start of the year. Brent, the global benchmark, is up around.
Prices have also gotten a lift from strong global demand and supply cuts by OPEC and Russia. But it's the Iran question that's driving short-term trading, experts say.
"We'll see what happens," Trump said last week about his decision on the Iran deal. "I'm not telling you what I'm doing, but a lot of people think they know."
Restoring sanctions on Iran could affect as many as 1 million barrels per day of crude supply.
But Shum said the impact is unlikely to be as severe as the multinational sanctions imposed on Iran in 2012.
That's because the European Union, whose members have been urging Trump not to pull out of the deal, may not go along with new sanctions. And China, a huge oil importer, could also push back.
Some American allies — including India, Japan and South Korea — are expected to cut Iran off, according to experts.
Although imposing sanctions on Iran would disrupt oil markets, the immediate impact on prices may end up being quite limited when the decision is actually announced because investors are already pricing it in.
"I don't think you should expect an acute spike given the fact that it's already been pretty well telegraphed," Brian Kessens, a portfolio manager at energy investment firm Tortoise Capital, said last week.