Jihadist fighters killed at least 10 soldiers in the western Iraqi province of Anbar on Tuesday in their latest deadly attack on security forces in the area, officers said.
The attack near the remote outpost of Rutba brought to at least 26 the number of members of the Iraqi security forces killed by the Islamic State group in the area in recent days.
"We had 10 soldiers killed and six wounded in an attack by Daesh early this morning," an army lieutenant colonel told AFP, using an Arabic acronym for IS.
A police officer and a local official confirmed the attack and casualty toll.
The army officer said IS fighters attacked a 1st Division base in the Saggar area, east of Rutba, using mortar rounds and rockets before fighters armed with rifles tried to storm it.
He said ensuing clashes lasted two hours until about 7:00 am (0400 GMT).
Rutba lies about 390 kilometres (240 miles) west of Baghdad in the vast province of Anbar and is the last sizeable town before the border with Jordan.
Anbar is a sprawling desert province traversed by the Euphrates River and borders Syria, Jordan and Saudi Arabia.
It has long been an insurgent stronghold, and IS already controlled parts of it when it swept through Iraq in 2014 to take over around a third of the country.
Pro-government forces have since retaken most towns and cities in Anbar, but the jihadists still control areas near the Syrian border and have desert hideouts from which they harass federal forces.
- Diversionary attack -
According to figures provided to AFP by several Anbar officials, at least 26 Iraqi personnel -- including members of the border guard, the army and the police -- have been killed in the area since April 23.
Military officials said IS was trying to breach the defence of Rutba, whose small size belies its strategic importance, as well as to create diversions to ease the pressure on its fighters in Mosul.
Sources in the coalition of Iraqi and foreign forces battling the jihadists say IS may only have a few hundred militants left in west Mosul.
A massive offensive was launched in mid-October to retake the country's second city, which was once the de facto capital of the now crumbling "caliphate" IS proclaimed nearly three years ago.
IS had carried out a number of diversionary attacks in the early stages of the operation, including on Rutba, but the group is apparently now stretched too thin to fight on many fronts.
These attacks are aimed "at opening gaps in the security set-up around Rutba to prepare for an attempt to recapture it," a local police colonel said.
"The Daesh organisation is also trying to ease the pressure on its fighters in Mosul by opening other fronts with the Iraqi security forces, especially in Anbar," he said.
A brigadier general in the Iraqi army estimated that IS still controls about 30 percent of Anbar province, by far Iraq's largest.
Rutba's mayor Imad al-Dulaimi called for additional forces to be deployed to his town in anticipation of a possible large-scale attack.