BAGHDAD -- A wave of suicide bombings by Islamic State militants in western Iraq has killed 40 soldiers amid waning efforts by security forces to retake territory from the Sunni extremist group, a senior Iraqi commander said Monday.

The attacks, which occurred on Sunday in the town of Sijir, 70 kilometres (43 miles) west of Baghdad, dealt a heavy blow to government efforts to rein in the militants whose rampage has seized much of the country's north and west this summer -- even as Iraqi Kurdish peshmerga fighters are starting to get training by Iraq's Western allies in the battle against the Islamic State group.

In addition to the 40 troops killed in the suicide bombings, 68 Iraqi soldiers were apparently captured by the Islamic State group in Sijir and have likely been taken to the nearby city of Fallujah, said Gen. Rasheed Fleih. There has been no communication with any of the soldiers since their capture Sunday, Fleih said.

On Sunday, the militants launched a massive wave of attacks on Iraqi troops in Sijir, involving several suicide bombings and sparking clashes, said a security official, speaking on condition of anonymity because he was not authorized to talk to the media. After the attacks, the Iraqi military withdrew 700 more troops stationed in the area, he added.

Following their battlefield successes in both Iraq and neighbouring Syria, fighters with the Islamic State group, among them many Iraqi nationals, re-entered Iraq through the country's western Anbar province, engaging in fierce battles with the Iraqi military. In this Sunni-majority territory, the group quickly capitalized on long-standing grievances against the Shiite-led government in Baghdad, earning support from local populations.

Iraqi and Kurdish security forces, backed by U.S. airstrikes, were able to retake the strategic Mosul Dam and several small towns since airstrikes began. However, serious challenges remain, since many of the Islamic State fighters have taken refuge in busy cities with high civilian populations, such as Fallujah and Mosul.

In northern Iraq, Kurdish fighters battling the Sunni militant group have begun receiving training from Western allies, including the United States, as they seek to beef up their capabilities, a top Kurdish security official said Monday.

Helgurd Hikmet, general director of the ministry overseeing Kurdish military forces known as peshmerga, said that France, Italy and Germany are also among countries providing training to help Kurdish forces use new machine-guns, mortars, rockets and demining robots they have received.

"We asked all our allies, when they provided us with new weapons, that these weapons need training," Hikmet told The Associated Press. "So now all the allies that provided us with those weapons are providing us with training."

The U.S. launched airstrikes and humanitarian missions in August to aid Iraqi and Kurdish security forces in northern Iraq.

Last week, the French joined in the aerial campaign. A number of European countries have also committed to arming the Kurds and providing humanitarian support for more than a million people displaced by the onslaught of the Islamic State group.

U.S. forces working with the peshmerga are part of the advise-and-assist teams that have been in Irbil, the provincial capital of the semi-autonomous Iraqi Kurdish region, for several weeks. The U.S. has also provided equipment against roadside bombs and other sophisticated artillery to the Kurdish fighters.

After seizing Iraq's second-largest city, Mosul, in June, militants with the Islamic State group waged an aggressive offensive across northern Iraq, forcing hundreds of thousands from their homes and coming dangerously close to heavily populated cities in Iraq's Kurdish region.

On Monday evening, a car bomb went off in the commercial district of Ur in eastern Baghdad, killing 12 people and wounding at least 28 others, police and hospital officials said.

The attack brought the day's death toll in and around Baghdad to 26. A bombing and a shooting earlier in the day killed seven while a midday bomb in a commercial street in Baghdad's southwestern district of Bayaa killed four people and wounded 13, according to police officials. All the officials spoke on condition of anonymity because they were not authorized to release the information.

Also, just north of Baghdad, gunmen broke into the house of an anti-militant Sunni fighter, killing his two sons and a daughter, the police said. The Sunni fighter was wounded along with his wife. He was a member of Sahwa, a Sunni militia that joined U.S. troops in the fight against Iraq's al-Qaida branch at the height of Iraq's insurgency in 2007 and 2008.