John Bacon

USA TODAY

Islamic State militants struggled to hold ground on two fronts Sunday as Iraqi troops drove out pockets of resistance in Fallujah, while Syrian government forces pressed closer to the effective militant capital of Raqqa.

The military gains, however, have done little to improve the dire humanitarian crisis facing the region.

In Iraq, the Amiriyah Fallujah District Council said security forces had liberated more neighborhoods in northern Fallujah from Islamic State control, killing dozens of militants. District Council member Khodier al-Rashed told Iraqinews.com that security forces detonated multiple suicide bomb vehicles.

The gains were announced two days after elite Iraqi forces, backed by U.S.-led coalition airstrikes, punched through Islamic State defenses in Fallujah, seizing the municipal compound and other buildings in the center of the city. The breakthrough brought momentum in the offensive that has raged for weeks, Iraqi officials said.

Caroline Gluck, spokeswoman for the United Nations High Commissioner for Refugees, said refugee camps were overwhelmed in recent days as thousands of Fallujah families sought safety from the fighting.

51 State Department officials urge strikes in Syria

“Agencies are scrambling to respond to the rapidly evolving situation," Bruno Geddo, the UNHCR's representative in Iraq, said in a statement. "We are bracing ourselves for another large exodus in the next few days as we estimate that thousands more people remain trapped in Fallujah."

In Syria, where humanitarian issues have been equally dire, government forces advanced to within a few miles of the Islamic State-occupied Tabqa air base, the Associated Press reported. The base, about 30 miles from Raqqa, was overrun by militants almost two years ago. Government forces also recaptured the nearby Thawra oil field, the AP said.

The Syrian gains came days after more than 50 officials with the U.S. State Department signed a confidential document calling for targeted military strikes against Syrian forces with a goal of regime change, The New York Times first reported. The officials cited continued breaches by Syrian forces of a cease-fire agreement designed to protect U.S.-backed Syrian rebels seeking to oust President Bashar Assad.