The Islamic State has taken control over most of Ramadi, the capital city of western Iraq's Anbar province, after raising their black flag over the main government building early May 15, local officials are reporting.
An Iraqi military official told dpa that "around 90 percent of Ramadi is now under the control of Daesh (IS)," while Reuters also reported that most of the city had been overrun.
If Ramadi were to fall, it would be the first major city seized by the insurgents in Iraq since security forces and paramilitary groups began pushing them back last year.
Ramadi, 110 kilometers west of Baghdad, is one of the few cities to have remained under government control in the vast desert province of Anbar, which borders Saudi Arabia, Syria and Jordan.
U.S. military officials played down the militant group's gains, suggesting they had been exagerrated.
But Vice President Joe Biden spoke May 15 with Iraqi Prime Minister Haider al-Abadi and pledged the United States would expedite U.S. aid to Iraqi forces.
"This will include delivery of heavy weaponry, including AT-4 shoulder-held rockets to counter vehicle-borne improvised explosive devices, additional ammunition, and supplies for Iraqi forces," the White House said in a statement.
Abadi pledged to intensify efforts to "expel the terrorist gangs from Ramadi."
The governor of Anbar province, Sohaib al-Rawi, said "the situation in Ramadi is dire, but the city has not fallen and the battle against criminal Daesh is still ongoing," Reuters reported.
Ramadi has been fought over for months, with the insurgents renewing their offensive there in April.
Their gains have crushed the government's hopes of regaining control over Anbar and then moving north to retake the Islamic State stronghold of Mosul.
An Iraqi army major whose regiment is positioned near the Anbar operations command told Reuters the militants had taken control of the only major supply route into Ramadi, making it difficult to send reinforcements.
Most army and police units have retreated to the area around the operation command to protect it, he said.
But some elite counterterrorism forces were "fighting for their lives" in the Malaab district of central Ramadi, where they were surrounded, he said.
"If the government does not send any reinforcements and the coalition air force does not rescue us, we will lose all of Ramadi," the major said.
"A massacre will take place and all of us will be slaughtered. We have been defending the city for months and we don't deserve to end like this. It's humiliating."
Still, the U.S. military asserted in a Pentagon news conference May 15 that the militants were "on the defensive" in Iraq.
Marine Corps Brigadier General Thomas Weidley, chief of staff for U.S.-led coalition operations, said Iraqi forces still controlled most "key facilities, infrastructure and lines of communication" in the Ramadi area.
They "will eventually take back the terrain," he said via teleconference from his headquarters in Kuwait.
But an Iraqi military officer told dpa that the United States sent planes to evacuate American military experts from al-Habania airbase, east of Ramadi.