The US claims to have destroyed or damaged 84 of 85 targets in Iraq and Syria

(CNN)- The US destroyed or damaged 84 of 85 targets in its wide-ranging airstrikes in Syria and Iraq on Friday, with no sign of Iranian casualties, according to two US defense officials.

All but one of the 85 targets were “destroyed or functionally damaged,” officials said, citing a preliminary assessment of battlefield damage.

A full post-strike analysis is still underway, but there is no indication that members of Iran's Islamic Revolutionary Guard Corps were killed as part of the operations, an official said.

In response to a drone strike in Jordan last weekend that killed three American service members and wounded dozens, the United States struck facilities and weapons used by the Islamic Revolutionary Guard Corps and Iran-backed groups in Iraq and Syria.

This was the first time that the United States had attacked both countries simultaneously. In Iraq, the US launched airstrikes on Al Qaim and Aghashad near the Syrian border. Also in Syria, the US launched strikes near al-Baram, Deir es-Zur and al-Mayadeen. The list of targets includes command and control centers, intelligence centers, rockets, missiles, drone storage facilities and more.

Speaking to reporters Friday after the attacks, Director of the Joint Chiefs of Staff Douglas Sims said the targets were chosen “with the idea that there might be casualties associated with people inside those facilities.”

The Biden administration has faced criticism for waiting too long to respond to a deadly drone strike in Jordan, giving Iranian-backed militias in Iraq and Syria time to redeploy their personnel. Sims noted Friday that favorable weather for the operation did not arrive until Friday night.

US President Joe Biden and Defense Secretary Lloyd Austin said the strikes were the beginning of a US response, far larger than previous US operations in Iraq or Syria.

National Security Adviser Jake Sullivan told CNN's Dana Bash on Sunday's “State of the Union” that the U.S. response to the attack that killed three U.S. service members is far from over. Sullivan called Friday's attacks “the beginning of our response and there will be many more steps.”

After the US attack, US forces were attacked on Saturday at the Euphrates mission support base, also known as the Conoco oil fields, according to one of the security officials. Two rockets were fired at the site, and no injuries or damage were reported.