BAGHDAD (AFP) - Iraq aims to complete the "liberation" of the strategic northern Shi'ite town of Tal Afar from militants in a matter of hours, a security spokesman said on Wednesday.

Security forces plan to accomplish "the liberation of the entire town by dawn on Thursday," the spokesman said, after which they will head for militant-held areas in the city of Mosul, to its east.

Iraqi forces pushed into new areas of Tal Afar on Wednesday during heavy fighting with militants, a provincial councillor said.

The Shi'ite-majority town is the largest in the northern province of Nineveh not to fall to militants, and is located along a strategic corridor to Syria.

It has been the scene of fierce fighting for days.

A major militant offensive, spearheaded by jihadists but involving others including supporters of ousted dictator Saddam Hussein as well, began in Nineveh's capital Mosul on June 9.

The militants took Mosul the following day, swept through Nineveh and took major parts of three more provinces as well.

Security forces generally performed poorly when faced with the initial assault, in some cases shedding uniforms and abandoning vehicles to flee.

They seem to have recovered at least somewhat from the shock of the onslaught, gaining ground in some areas, but militants have made advances elsewhere.