Iraqis celebrated on Friday the killing of top Iranian commander Qasem Soleimani in a US airstrike in Baghdad.
A video showed Iraqis dancing in the street.
"Iraqis — Iraqis — dancing in the street for freedom; thankful that General Soleimani is no more," Pompeo wrote, alongside footage of scores of people running along a road and waving what appeared to be Iraqi flags and other banners.
President Donald Trump ordered the killing of the Iran Revolutionary Guards commander, who died Friday "in a decisive defensive action to protect US personnel abroad," the Pentagon said.
"General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region," the Department of Defense said in a statement.
"General Soleimani and his Quds Force were responsible for the deaths of hundreds of American and coalition service members and the wounding of thousands more."
The strike at Baghdad's international airport also killed the deputy chief of Iraq's Popular Mobilization Forces (PMF).
A pro-Iran mob this week laid siege to the US embassy following deadly American air strikes on Kataib Hezbollah.
The US had called the strikes in response to a rocket attack days earlier that killed an American contractor working in Iraq.
The Pentagon said Soleimani had orchestrated attacks on coalition bases in Iraq over the past months, including on December 27, the day the contractor was killed.
"General Soleimani also approved the attacks on the US Embassy in Baghdad that took place this week," it said.