Militants in Iraq have used stolen Humvees loaded with explosives to unleash a series of suicide car bombings targeting Iraqi security forces, killing at least 18 Iraqi troops.
The attacks came as the government pressed on with efforts to reclaim territory under the extremists' control in the embattled western Anbar province.
First, back-to-back suicide bombers rammed their Humvees into Iraqi forces deployed outside the University of Ramadi complex near the Islamic State-held city of Ramadi, the provincial capital of Anbar, killing at least 12 troops in that attack.
Officials said that eight Iraqi soldiers were wounded in that bombing.
Later, another suicide bomber drove an explosives-laden Humvee toward army and paramilitary forces near Fallujah, which lies half-way between the capital, Baghdad, and Ramadi, killing six troops and wounding four others.
Iraqi government forces recaptured the Ramadi university, located south of Ramadi, from IS militants on Sunday, as part of their broader offensive. IS captured Ramadi, the provincial capital, in mid-May.
Clashes also continued south west of Ramadi, killing one soldier and wounding eight others, officials said, while 14 militants were also killed.
Some militants were still holed up in some buildings inside the university complex and ground forces have asked for air strikes. Some of the complex buildings and streets were rigged with bombs, preventing the Iraqi troops from moving easily.
Earlier this month, Iraqi military launched a large-scale operation to dislodge militants from Anbar, in which most of the biggest cities are held by the Islamic State group.
The fall of Ramadi recalled the collapse of Iraqi security forces last summer in the face of the Islamic State group's blitz across Iraq that saw it capture a third of the country, where it has declared an Islamic caliphate, along with the territory it controls in neighbouring Syria.
Government-backed forces, which include the Iraqi military, Shiite militias and Sunni tribes, are also currently assembling around the militant-held city of Fallujah, which was the first major city in Iraq to fall to the militant group in early 2014.