Iraqi forces have cut ISIS' last supply line into the western city of Ramadi by seizing a key bridge, Iraqi officials and a military officer said Thursday. The capture of Palestine Bridge, straddling the Euphrates River in northwestern Ramadi, means Iraqi forces have the city surrounded. They will now move to clear the city of the militants one neighborhood at a time. "The bridge is now entirely under our control," said Sabah al-Numani, spokesman for the Iraqi counterterrorism forces, which are deployed on the western side of the bridge along with federal police. "We are tightening our grip on them [ISIS]." Ramadi, the capital of Anbar province, fell to ISIS in May, dealing the biggest blow in nearly a year to government forces and dampening hopes of routing the militants from the country's north and west. Prime Minister Haider al-Abadi vowed a quick counteroffensive to retake the city. But that was held up by homemade bombs, inadequate troops and equipment due to government cash shortages, and stringent rules of engagement for U.S.-led airstrikes, Iraqi army and federal police officers involved in the battle previously told Reuters. An army colonel from the 9th division, on the eastern side of Palestine Bridge, said the latest advance had been aided by intensified airstrikes from the U.S.-led coalition, and that explosive disposal teams were preparing to clear the way. "This advance is very important," the colonel said on condition of anonymity. "Daesh [ISIS] can no longer ferry weapons, food and equipment through the river like they did in the past." Retaking the city would be a major psychological boost for Iraqi security forces, which partially collapsed when ISIS overran around one-third of Iraq, a major OPEC oil producer and U.S ally. Defense Ministry spokesman Tahsin Ibrahim confirmed the bridge had been retaken, isolating ISIS militants inside Ramadi from their strongholds further west in Anbar province and Syria. The ultimate goal for Iraqi forces is to break ISIS' grip over the northern city of Mosul. Kurdish forces recently recaptured the city of Sinjar in northwestern Iraq, cutting an important supply line between Mosul and the city of Raqqa, ISIS' de facto capital in Syria.