That's the explanation by analysts:
"WTI crude oil futures extended recent gains to above $71 per barrel on Monday, supported by supply risks following new US sanctions on Iran's crude exports. The US Treasury announced sanctions last week targeting individuals and tankers involved in transporting millions of barrels of Iranian crude annually to China, aiming to increase pressure on Tehran. However, oil gains were limited by persistent concerns over the potential fallout from President Donald Trump’s ongoing tariffs. Over the weekend, Trump announced new global tariffs on steel and aluminum, which could affect the US energy sector, including oil drillers reliant on specialty steel not produced domestically. Meanwhile, Chinese tariffs on US goods take effect today in retaliation for Trump’s recent levies, though their impact is expected to be limited due to China’s modest US energy imports."
https://tradingeconomics.com/commodity/crude-oil