United Nations Secretary-General António Guterres was "deeply concerned" after a U.S. strike killed one of Iran's top generals, according to Guterres's spokesman.
Farhan Haq, the secretary-general's deputy spokesman, said in a statement that the leader has "consistently advocated for de-escalation in the Gulf."
"He is deeply concerned with the recent escalation," Haq said. "This is a moment in which leaders must exercise maximum restraint. The world cannot afford another war in the Gulf."
Other world leaders have also criticized the U.S. decision to launch an airstrike against Gen. Qassem Soleimani.
"We are waking up in a more dangerous world. Military escalation is always dangerous,” said Amelie de Montchalin, French deputy minister for foreign affairs, in a recent interview.
"Such actions don’t help resolve complicated problems in the Middle East, but instead lead to a new round of escalating tensions,” said a statement from Russia's foreign ministry.
Secretary of State Mike PompeoMike PompeoChristie, Pompeo named co-chairs of GOP redistricting group America needs a new strategy for Pacific Island Countries Harris to hold fundraiser for McAuliffe ahead of Virginia governor's race MORE pushed back on these characterizations Friday in a CNN interview.
"The world's a much safer place today, and I can assure you that Americans in the region are much safer today after the demise of Qassem Soleimani," he said.
He has also said that the action was in response to "imminent threats to American lives" and that Soleimani was planning actions "that would have put dozens if not hundreds of American lives at risk."
Iran, meanwhile, has threatened "harsh retaliation" for the attack.
The death of the Iranian general follows an escalation in tensions between the U.S. and Iran, when an Iranian-backed militia and the group's supporters stormed the U.S. Embassy in Baghdad in protest on Tuesday. The demonstrations were a response to another U.S. airstrike that was aimed at Kataib Hezbollah groups in Syria and Iraq, which killed 25 militia fighters.
The U.S. fired on Kataib Hezbollah forces after the Trump administration blamed the organization for an attack that killed an American contractor and wounded several U.S. service members.
The U.S. and Iran have had a strained relationship since Trump pulled the U.S. out of the Obama-era Iran nuclear deal in 2018. In recent months, tensions have escalated amid an attack on Saudi oil facilities that the U.S. blamed on Iran.