It follows reports from the Wall Street Journal that US President Donald Trump has instructed aides to prepare to extend the ongoing blockade of Iran's ports, in an effort to squeeze the country's economy. BBC reported.
Iran has said it will continue to disrupt traffic travelling through the Strait of Hormuz in response to the US blockade.
The price of oil has seen sharp swings since the start of the war, as the key Strait of Hormuz has been effectively closed for weeks due to the conflict.
Iran has severely restricted shipping through the strait — which usually carries about a fifth of the world's supply of oil and liquid natural gas — in response to US and Israeli strikes that began on 28 February.
Earlier this month, Tehran warned that any vessel that approaches the strait would be targeted.
The US then announced that its forces would intercept or turn back vessels travelling to or from Iran's ports.
Analysis by BBC Verify shows that at least four vessels tracked from Iranian ports appear to have crossed the US blockade line.
Despite the fluctuations of recent weeks, the price of oil remains much higher than the pre-conflict price of a barrel.
The price of Brent crude dropped to $90 a barrel on 17 April, after a ceasefire between Israel and Lebanon was announced. The US said it would pause attacks on Iran on 8 April. It remains much higher than the pre-conflict price of a barrel.
However, the oil benchmark has been rising steadily over the last 12 days, as the US continued its blockade.
