Iraqi government forces advancing on the Islamic State-held city of Mosul retook a village from IS on Tuesday and linked up along the Tigris river with army units pushing from a separate direction, Defence Minister Khalid al-Obeidi said.

The territorial gain, which followed the recapture of a key air base nearby at the weekend, further isolated Mosul in preparation for a government assault to recover Iraq's second largest city 60 km (40 miles) to the north.

"Forces from the 9th Armoured Division and the counter-terrorism service liberated Ajhala village north of Qayara base," Obeidi said on Twitter.

"Our heroes arrived at the riverbank and made contact with Nineveh Liberation Operation units," he added, referring to troops who had set out from Makhmour, 25 km east of the Tigris, in March.

The newly retaken territory still needs to be secured since IS insurgents remain holed up in several towns behind the government's front line, a military spokesman said.

Backed by air support from a U.S.-led military coalition, government forces on Saturday regained Qayara air base, which is to be turned into a logistics hub for the main assault on Mosul.

On Monday, U.S. Defense Secretary Ash Carter announced the dispatch of 560 additional soldiers to Iraq, most of whom will work from Qayara to assist the Iraqi thrust towards Mosul.

Prime Minister Haider al-Abadi has pledged to retake the city, the largest still held by IS, by year-end, but there is still debate in Washington about the timing of any move.

Suicide bombings like the one in Baghdad on July 3 that killed nearly 300 people, one of the largest attacks since the U.S.-led invasion that toppled Saddam Hussein 13 years ago, suggest the group could remain a long-term threat.

IS claimed another car bomb on Wednesday in Baghdad's northern outskirts that left nine people dead, according to medical and security sources.

On Wednesday, Abadi's government urged the postponing of demonstrations called for by powerful Shi'ite Muslim cleric Moqtada al-Sadr later this week to pressure political leaders to implement long-promised reforms.

A statement from Abadi warned the protests could land the country in "chaos ... and end up serving the goals of the enemy and its terrorism".

Sadr, whose supporters twice stormed Baghdad's heavily fortified Green Zone earlier this year, called for a reprieve from protests during the Islamic holy month of Ramadan, which ended last week. – Reuters