Iraqi forces took the northern edge of the Islamic State-held town of Hit, west of Baghdad, on Sunday in an operation led by the country's elite counter-terrorism forces, military officials said.
The operation to recapture Hit was relaunched last week, but the troops' progress has been slowed by hundreds of roadside bombs and efforts to safeguard thousands of civilians trapped inside the town.
"We've never had a delay like this on one of our targets," said General Husham al-Jabri of Iraq's counter-terrorism forces.
The initial push to take Hit was launched last month, but was quickly put on hold when Iraq's Prime Minister Haider al-Abadi pulled forces back to Baghdad after anti-government protests threatened instability in the Iraqi capital.
After the operation resumed, Iraqi forces had to deal with hundreds of roadside bombs laid by IS fighters along the main roads leading in and out of Hit, forcing convoys to veer off into the surrounding desert terrain.
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Even there, the forces' advance was repeatedly brought to a standstill by booby-trapped explosives. Progress was further complicated by muddy conditions after days of rainfall.
While initially used on a limited basis by al-Qaeda in Iraq, the predecessor to the Islamic State group, IS now produces roadside bombs on an industrial scale.
Iraqi forces have struggled to train and equip enough units to deal with the sheer volume of the bombs.
The US-led coalition said Iraqi forces were in the outskirts of Hit and working to surround the town, seeking to build on recent gains made by government forces with the recapture in February of Ramadi, the capital of Anbar Province in central Iraq.
Hit, 140 kilometres west of Baghdad, lies along a supply line linking the extremist group's fighters in Iraq with those in neighbouring Syria.
