Militants killed at least 18 Iraqi officers and soldiers in Sunni-dominated Anbar province today, including a commander who oversaw a crackdown on Sunni protesters earlier this year, military sources said.
Islamist militants' posts on online forums called the slain commander, Mohammed Ahmed al-Kurwi, a "criminal" and celebrated the attack, which security sources described as carefully planned and executed.
Al Qaeda-linked Sunni militants have intensified attacks on Iraq's security forces, civilians and anyone seen as supporting the Shi'ite-led government in recent months in the country's deadliest violence in five years.
The circumstances of the attack were in dispute.
The Defence Ministry said Kurwi, commander of the army's Seventh Division, and several other high-ranking officers were killed by a roadside bomb while pursuing militants from an al Qaeda training camp in Anbar's desert.
But other military sources said the officers were killed when three suicide bombers wearing explosive belts detonated themselves among them in the western town of Rutba, 360 km (225 miles) west of Baghdad.
"All that we know so far is three suicide bombers wearing explosive vests came from nowhere and detonated themselves among the officers," a military officer who was at the scene told Reuters by phone.
Some security officials suggested informants may have lured the commanders to the area under the pretext of raiding the al Qaeda camp.
No specific group immediately claimed responsibility for the attack, but suicide bombing is the trademark of al Qaeda's Iraqi affiliate, which merged this year with counterparts in Syria to form the Islamic State of Iraq and the Levant (ISIL).
The assistant commander of the Seventh Division, the commander of its 27th Brigade, and several other high-ranking officers were also among those killed in the attack, sources said. Another 32 soldiers were wounded.
Militant Islamists online portrayed Kurwi's death as retribution for the killings of more than 40 people in a raid by security forces on a Sunni protest camp in the northern town of Hawija in April.
"The criminal who was killed today at the hands of al-Baghdadi's men was the leader of the Hawija massacre," said one user on Twitter, referring to ISIL leader Abu Bakr al-Baghdadi.
The April raid - which Kurwi oversaw - came after months of protests by Sunnis against what they see as marginalisation of their sect by Prime Minister Nuri al-Maliki's government.
ISIL insurgents have since stepped up attacks on strategic targets in parts of western Iraq in a bid to establish a state ruled by strict Sunni Islamic practice.
In a separate incident, the commander-in-chief of the police force in Shirqat, 300 km north of Baghdad, was killed and four of his officers were wounded when a roadside bomb exploded by his convoy, police and medical sources said.
Another two soldiers were killed when a roadside bomb went off as their military patrol was passing through Riyadh, a small town near Hawija, police said.
In Latifiya, a town 40 km south of Baghdad, two Shi'ite pilgrims were killed by rocket fire, police said. Another two Shi'ites were killed when militants raided a supermarket in the capital's southeast.
Iraqi security services are expecting more attacks ahead of the Shi'ite holy day of Arbaeen next week.