A statement from Iraq's joint operations command coordinating the fight against the Islamic State group said forces retook several villages from the jihadists along the Euphrates River.
The Iraqi army's 7th division had been moving down the river from Al-Baghdadi and eventually joined up with forces from the counter-terrorism service moving up from the town of Heet.
"The road is therefore open between Heet and Haditha, via Al-Baghdadi, after an 18-month siege by the terrorists of Daesh," the statement said, using an Arabic acronym for IS.
However, a commander of Haditha's tribal fighters said the area of Al-Dulab, which lies in a loop of the Euphrates just east of Al-Baghdadi, was still in IS hands.
More From This Section
"The people are hopeful but for now nobody will take the risk of travelling on this road so long as Al-Dulab has not been retaken," Sheikh Abdullah al-Jughaifi told AFP by phone from Haditha.
Haditha, 210 kilometres (130 miles) northwest of the capital Baghdad, is the third city in the vast province of Anbar and lies near the country's second largest dam.
For months, the city's main lifeline was the nearby military base of Al-Asad, which was only accessible by air.