Israel has provided Washington with satellite images of ISIL targets in Iraq, as well as information about Western citizens suspected of joining the terrorist organization, a Western diplomat told Reuters on Monday.

The diplomat said Israeli spy satellites, flying over Iraq at angles and frequencies unavailable from US satellites, had provided images that allowed the US military to "fill out its information and get a better battle damage assessments" after strikes on ISIL in Iraq.

But the Israeli-supplied intelligence would reach the US "with the Hebrew and other markings scrubbed out" to avoid angering the Arab and Turkish governments who are supporting the terrorist group, the diplomat said.

Tel Aviv has not denied involvement of the military effort against ISIL, also known as ISIS or IS.

"We don't comment on any assistance by us, or if there is such assistance, in the fight against ISIS," an Israeli military spokesman said.

The revelation comes as the US tries to unite an international coalition against ISIL. The Pentagon has already carried out more than 120 airstrikes against ISIL targets in Iraq since August 8.

ISIL militants were trained by the CIA in Jordan in 2012 to fight the Syrian government.

The militant group now controls large parts of Syria's territory and sent its fighters into neighboring Iraq in June, quickly seizing vast expanse of land straddling the border between the two countries.