Iraqi forces advanced into the city of Ramadi on Dec. 21 in an effort to liberate the city from Islamic State control. By Tuesday, the soldiers made their way toward the center of the city.

As the BBC reports, the troops and their allies have reclaimed two districts.

Ramadi was taken over by the Islamic State in May after a five-month-long battle. Since July, the Iraqi government has tried to take back the city several times. Monday’s advance, which utilized soldiers, police officers and Sunni tribesmen, has been the most successful attempt so far.

On Tuesday, the U.S. lent its air support to the advance by conducting 12 strikes around the city.

As reported by The New York Times, U.S. military spokesman Col. Steven H. Warren acknowledged the progress the Iraqi troops were making.

“They are moving into the city center,” he said.

As The Wall Street Journal reports, Warren expressed optimism about the advance.

“I think the conditions seem to be looking good for Iraqi security forces to make some progress,” he said.

Gen. Sabah al-Numani, a spokesman for the Iraqi counterterrorism unit behind the offensive, said the advance was initiated from different points. He predicted that Ramadi would be cleared of the Islamic State within the next 72 hours.

According to an anonymous security official in Anbar Province, ISIS met the advance by preventing the people of Ramadi from leaving the city.

The Islamic State has controlled around one-third of Iraq since the middle of 2014. Taking control of Ramadi would be a major feat for Iraq.

“Victory in Ramadi means a victory for Iraqi security forces,” Iraqi military spokesman Brig. Gen. Yahya Rasool said.

According to Rasool, the advance means that Iraqi forces will now lead the fight against ISIS everywhere.