Britain, France, Germany, and Japan have tried to get the leaders of the United States and Iran to revive diplomacy while attending the annual UN General Assembly in New York this week.
Pakistani Prime Minister Imran Khan also said the United States and Saudi Arabia both asked him to mediate with Iran to defuse tensions.
U.S.-Iranian relations have soured ever since U.S. President Donald Trump last year withdrew from a nuclear accord with Tehran and reimposed sanctions on Iran that target its oil and financial industries.
French President Emmanuel Macron said on September 24 it would be "a lost opportunity" if Iranian President Hassan Rohani left the United States without meeting with Trump.
British Prime Minister Boris Johnson, who met with Rohani and Macron at the UN, supported Macron, saying, "I think I agree with Emmanuel [Macron]."
The leaders of Germany and Japan also held meetings with Rohani and Trump at the UN, urging them to meet.
Meanwhile, Khan told reporters that Trump had asked him to "de-escalate the situation and maybe come up with another [nuclear] deal."
Khan said he met with Trump on September 23 and then "immediately spoke to President Rohani," while adding that "we're trying and mediating."
The 2015 nuclear deal that also includes Britain, France, Germany, Russia, and China as signatories, was meant to curb Iran's nuclear program while lifting sanctions.
Trump on September 24 said Washington will instead intensify pressure on Iran.
Tehran has indicated that talks won't resume with the United States until the restrictive measures are eased.