10 January 2017: A Free Syrian Army (FSA) fighter reacts as he mourns near the body of his brother, who was an FSA fighter and died during an offensive against Islamic State fighters to take control of Qabasin town, on the outskirts of the northern Syrian town of al-Bab, Syria Khalil Ashawi/Reuters

The US military conducted air raids in Syria on Tuesday, (17 January) against Islamic State militants near the town of al-Bab amid criticism from Turkey for its insufficient support of the ground offensive.

US Air Force Colonel John Dorrian, a spokesperson based in Baghdad for US-led military coalition said that four air strikes hit the militant group's construction equipment, tactical units and an armored personal carrier. "We saw a window of opportunity where it was in our mutual interest to get those targets destroyed," and added that the raids were in the interests of both countries.

"This is something we expect to continue doing. We strike (Islamic State) targets anywhere in Syria or Iraq that they can be found," he said.

Dorrian added saying that targets were identified while working with Ankara and were mutually developed by both countries. The extent of US support to Turkey near the al-Bab region is not yet clear.

US' support for Kurdish fighters in Syria has reportedly irked Ankara as Turkey sees the group as an extension of PKK, which is considered as a terrorist organization by both countries.

There are at least 500 US troops in Syria and are a mix of special operation forces and elite personnel who concentrate on training and advising allies, including Turkey.

Ankara has seen significant casualties while fighting with IS (Daesh) militants entrenched in the al-Bab area, which is situated 20 miles south of Turkey's border with Syria.

Turkey also alleged that the US failed to do enough to back its efforts to recapture al-Bab from the extremist hardline group even as Turkey continues to provide the coalition with access to an air base to carry operations in Syria.