U.S. forces have begun scaling down their numbers in Iraq after Iraqi authorities declared "victory" over the Islamic State (IS) extremist group, an Iraqi government spokesman has said.

Saad al-Hadithi said on February 5 that the battle against IS had ended "and so the level of the American presence will be reduced."

Hadithi stressed that the drawdown was still in its early stages and at present did not mark the beginning of a complete withdrawal of U.S. forces.

Hadithi's statement came in confirmation of reports by Western contractors at a U.S.-led coalition base in Iraq, who said U.S. troops had started to withdraw from the country.

The reports said U.S. soldiers, weapons, and equipment were being transported out of Iraq to Afghanistan.

The contractors said dozens of U.S. soldiers had left on daily flights over the past week.

The United States first launched air strikes against IS in Iraq in August 2014 and in the following years closely backed key Iraqi military victories, including the retaking of Mosul, Iraq's second-largest city.

A Pentagon report released in November said there were amost 8,900 U.S. troops in Iraq as of late September.

Based on reporting by Reuters and AP