Editor's note: This story was originally published on June 30, 2016. It was updated July 1 with video footage of the air strike.
A massive convoy of 120 Islamic State vehicles was hit by U.S. and Iraqi bombs Wednesday night in Anbar province, marking one of the most deadly strikes on the extremist group in recent memory, defense officials said.
The rare concentration of Islamic State vehicles was spotted east of Ramadi moving westward when it was hit by a barrage of airstrikes from U.S. and Iraqi aircraft, defense officials said.
The attack comes after Islamic State militants were pushed out of Fallujah in a five-week battle that Iraqi army officials say ended Sunday.
The militants in the convoy may have been moving east to reinforce the Islamic State forces under attack near the Iraq-Syria border town of Abu Kamal, in the Euphrates River valley, defense officials said.
When the airstrikes began hitting the convoy, the militants abandoned their vehicles and fled on foot, defense officials said.
A separate set of strikes Tuesday night hit 55 vehicles operated by Islamic State militants, also known as ISIS or ISIL.
U.S. surveillance aircraft spotted the gathering of ISIS fighters and vehicles in a neighborhood southwest of Fallujah, west of the Tofaha Bridge, an area known to be a key ISIS outpost while the group controlled the city, defense official said.
U.S. aircraft unleashed dozens of guided munitions on the militants while Iraqi security forces attacked from the ground, defense officials said.
U.S. military officials declined to estimate how many ISIS fighters were killed in the two attacks.
The total size of the ISIS force in Iraq and Syria is between 19,000 and 25,000, according to official U.S. intelligence estimates earlier this year.
But the pair of massive strikes are just the latest attacks that are likely eroding the militants' combat power.
During the fight in Fallujah, the Islamic State group suffered more than 1,000 casualties and the Iraqi military detained another 1,000 extremists, said Army Col. Chris Garver, a spokesman for U.S. forces in Baghdad.
Those forces will be hard to replenish. The estimated flow of foreign fighters heading into Iraq and Syria to join the ranks of the Islamic State group has dropped from more than 2,000 fighters a month last year to current estimates as low as 200 per month, Garver said.