U.S. President Donald Trump said Chinese President Xi Jinping had agreed Tehran must reopen the Strait of Hormuz, though China gave no indication it would weigh in.
Flying back from Beijing, Trump said he was considering whether to lift U.S. sanctions on Chinese oil companies buying Iranian oil.
"I'm not asking for any favors because when you ask for favors, you have to do favors in return," Trump said.
China's foreign ministry expressed frustration with the Iran war, calling it a conflict "which should never have happened, has no reason to continue."
Iran effectively shut the strait after the U.S. and Israel launched attacks on February 28, causing the biggest oil supply crisis in history.
Oil prices rose around 3% to around $109 a barrel on Friday.
