Iraq on Tuesday launched a major operation to recapture areas north of Baghdad from the Islamic State (IS) group, sending thousands of security forces to fight the jihadists, officials said.

Some 7,000 counter-terrorism forces, soldiers, police and allied paramilitaries are taking part in the mission, an Iraqi army colonel who requested anonymity told the AFP news agency.

Iraq's Joint Operations Command said the operation is backed by artillery and both Iraqi and US-led coalition aircraft.

The targeted areas, which the colonel said extend from the city of Samarra up to the town of Baiji, are a corridor linking IS group-held territory around the northern city of Mosul, the jihadists' main hub in Iraq, with areas farther south.

The launch of the operation comes a day after four IS group suicide bombers infiltrated an army headquarters in the Haditha area of Anbar province, to the west of Baghdad, killing an Iraqi general and five other soldiers. Seven soldiers were also wounded in the attack, army and police officers said.

According to Colonel Faruq al-Jughaifi, the Haditha police chief, the bombers were wearing military uniforms.

Sources said Staff Brigadier General Ali Aboud and Lieutenant Colonel Farhan Ibrahim were among those killed.

Heavy tolls in Anbar

The IS group launched a devastating offensive in June 2014 that overran swathes of territory north and west of Baghdad, but Iraqi forces backed by US-led strikes have succeeded in regaining significant ground from the jihadists.

At the end of last year, Iraqi forces retook Ramadi, the capital of Anbar, from IS group fighters and are now turning their attention to areas to the north through which the jihadists have moved supplies and fighters to the province.

Iraqi tribesmen and security personnel defending Haditha, which lies near the country's second largest dam, have held off the jihadists for more than 18 months with the help of air strikes by a US-led coalition.

But the war against the IS group has taken a heavy toll on senior Iraqi officers in Anbar.

Two heads of the Anbar Operations Command were wounded in 2015, while the commanders of a division and a brigade were killed in Anbar in April of that year. The province's governor was wounded in 2014.

Senior army and police commanders have also been killed in other provinces.

(FRANCE 24 with AFP)