The general who oversaw the US raid on the leader of the so-called Islamic State group has said the country is on alert for possible “retribution attacks” by extremists.

General Frank McKenzie, head of US Central Command, said Abu Bakr al-Baghdadi’s remains were buried at sea within 24 hours of his death.

The Pentagon released the first government photos and video clips of the night-time operation, including one showing Delta Force commandos approaching the walls of the compound in which al-Baghdadi and others were found.

Another video showed American air strikes on other militants who fired at helicopters carrying soldiers to the compound.

The US also bombed the compound after the soldiers completed the mission so it would not stand as a shrine to al-Baghdadi.

“It looks pretty much like a parking lot with large potholes right now,” Gen McKenzie said.

The American force launched from an undisclosed location inside Syria for the one-hour helicopter ride to the compound, he added.

Two children died with al-Baghdadi when he detonated a bomb vest, the general said, adding that this was one fewer than originally reported.

He said the children appeared to be under the age of 12.

Abu Bakr al-Baghdadi
Abu Bakr al-Baghdadi was killed in the raid (Department of Defence/AP)

Eleven other children were escorted from the site unharmed, while four women and two men who were wearing suicide vests and refused to surrender inside the compound were killed, Gen McKenzie said.

He said the military dog that was injured during the raid is a four-year veteran with US Special Operations Command and had been on about 50 combat missions.

Gen McKenzie said the dog was injured when it came in contact with exposed live electrical cables in the tunnel after al-Baghdadi detonated his vest, but has returned to duty.

The dog, named Conan, will leave the Middle East and visit the White House next week, President Donald Trump said.

Al-Baghdadi was identified by comparing his DNA to a sample collected in 2004 by US forces in Iraq, where he had been detained.

Precision munitions destroyed the compound of Islamic State leader Abu Bakr al-Baghdadi
Precision munitions destroyed the compound (Department of Defence/AP)

The US collected “substantial” amounts of documentation and electronics during the raid, Gen McKenzie said, but would not elaborate.

Such efforts are a standard feature of raids against high-level extremist targets and can be useful in learning more about the group’s plans.

Although the raid was successful, the general said it would be a mistake to conclude that IS has been defeated.

“It will take them some time to re-establish someone to lead the organisation, and during that period of time their actions may be a little bit disjointed,” the general said.

“They will be dangerous. We suspect they will try some form of retribution attack, and we are postured and prepared for that.”

US Special Forces moved towards the compound
US special forces move towards the compound (Department of Defence/AP)

In outlining the operation, Gen McKenzie said al-Baghdadi had been at the compound in Syria’s north-west Idlib province for “a considerable period”, but he was not specific on the timeline.

He said President Donald Trump was briefed on Friday, and Gen McKenzie made the decision to go ahead on Saturday morning.

He offered no new details about al-Baghdadi’s final moments.

“He crawled into a hole with two small children and blew himself up while his people stayed on the grounds,” he said when asked by a reporter about al-Baghdadi’s last moments and Mr Trump’s description of the IS leader as “whimpering and crying and screaming all the way” to his death.