The Turkish military said it responded to the attack on the Bashiqa camp -- used to train Iraqi anti-jihadist fighters with Turkish help -- with fire of its own.

"Four Turkish troops were wounded in a mortar attack against the military training camp near Mosul," the Turkish official told AFP, emphasising that the attack originated from IS-held territory.

"All four servicemen have since been evacuated and are currently undergoing medical treatment. We are pleased to confirm that their condition is stable," added the official, asking not to be named.

The army confirmed the attack in a statement, saying it took place in the context of clashes between IS fighters and Kurdish peshmerga fighters at 3:10 pm (1310 GMT).

"The fire was responded to with return fire in kind on targets" belonging to IS, the army said. "This attack shows once again the importance of security measures for the contingent" in Bashiqa, it added.

According to CNN-Turk, IS jihadists fired up to 60 mortar rounds over several hours.

One of the Turkish troops was seriously wounded but his life is not in danger, it added. The army said all four had been taken for treatment in the Sirnak province on the Turkish side of the border.

Turkey earlier this month announced that hundreds of troops had been deployed at the Bashiqa camp to protect Turkish military who were training local Iraqi fighters seeking to recapture Mosul from the IS.

But the deployment outraged the central Iraqi government in Baghdad, which bitterly complained to Ankara and said it would take the issue to the UN Security Council.

In a bid to placate Baghdad, an unspecified contingent of the Turkish troops this week pulled out of the camp and headed northwards.

The move came after Turkish Prime Minister Ahmet Davutoglu last week sent foreign ministry under-secretary Feridun Sinirlioglu and intelligence chief Hakan Fidan to Baghdad on a mission to settle the tensions.

The Iraqi government on Tuesday demanded the "complete withdrawal" of Turkish forces from its territory, indicating Ankara's partial pullout the previous day was not enough.

By contrast, the deployment has been supported by the Kurdistan Regional Government (KRG) which controls the northern Iraqi region and has excellent relations with Ankara.