REUTERS

"The Secretary-General has consistently advocated for de-escalation in the Gulf," said Farhan Haq, deputy spokesperson for the secretary-general, according to CNN.

"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."

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Iran's top security and intelligence commander was killed early Friday in a drone strike at Baghdad International Airport that was authorized by President Trump, American officials said. The commander, Maj. Gen. Qassem Soleimani, who led the powerful Quds Force of the Islamic Revolutionary Guards Corps, was killed along with several officials from Iraqi militias backed by Tehran when an American MQ-9 Reaper drone fired missiles into a convoy that was leaving the airport, according to The New York Times.

General Soleimani was the architect of nearly every significant operation by Iranian intelligence and military forces over the past two decades, and his death was a staggering blow for Iran at a time of sweeping geopolitical conflict.

United States officials were braced for potential Iranian retaliatory attacks, possibly including cyberattacks and terrorism, on American interests and allies.