In another twist of alliances, the Syrian government has been bombing ISIS bases for the past 24 hours in coordination with the Iraqi government.

The Syrian bombings were concentrated on ISIS stronghold cities, Raqa and Hasakah. According to the Syrian Observatory for Human Rights (SOHR), Syrian regime planes targeted a local government building, the ISIS headquarters, a Sharia court ISIS runs and the Palace of Hospitality in Raqa. Unconfirmed photos from activists in Raqa support the claim.

ISIS took the cities early in the Syrian Civil War and have implemented a brutally strict Sharia system there.

According to AFP, the bombing campaign was prompted by ISIS moving heavy weaponry, including tanks in from Iraq, presumably captured from the Iraqi military. SOHR director Rami Abdel Rahman called it the regime’s most “intense” bombings of ISIS yet.

Iran has also been assisting in the fight against ISIS. Some 2,000 troops from the Basij volunteer militia crossed the border Sunday. Troops from Iran’s elite Revolutionary Guard moved into Iraq to protect holy Shi’ite sites and retake towns after ISIS gained significant ground in northern Iraq last week.

Iranian president Hassan Rouhani opened up the possibility of working with the U.S. to fight the jihadists threatening to completely destabilize Iraq.

The Syrian government and ISIS have largely turned their attention away from each other in recent months. Both have concentrated their attacks on rebel groups in Syria, of which there are dozens. ISIS is concentrated more on establishing an Islamic state than fighting the Assad regime and evidence of oil sales with the Assad regime has prompted experts to suggest ISIS and the Assad regime have actually worked together

The Obama administration is weighing its options with respect to helping Iraq combat ISIS. President Obama has ruled out sending ground troops but could order drone and manned airstrikes on ISIS positions. On Saturday, Defense Secretary Chuck Hagel ordered the U.S.S. George H.W. Bush to the Persian Gulf.