It was not immediately possible to independently confirm the claim made on one of the group’s Twitter accounts.

The ISIS Twitter site said the fighter jet had been shot down as it conducted a raid on areas north of Ramadi, the provincial capital of Sunni heartland Anbar.

A member of an anti-ISIS Sunni force called Sahwa (Awakening) said an Iraqi fighter jet, a Russian-made Su-25, was seen in flames as it crashed after being shot down north of Ramadi, according to Reuters.

Iraq’s government relies on a U.S.-led coalition and Iranian-backed Shi’ite militias in its fight against ISIS, which holds a third of the country as well as parts of neighboring Syria.

ISIS militants seized Ramadi last month and the city is a focal point of efforts to slow the group’s advances in Iraq, a major oil producer and OPEC member.