BAGHDAD (AP) — The Islamic State extremist group launched an offensive Wednesday in Iraq's western Anbar province, capturing three villages near the provincial capital of Ramadi in what was the most significant threat to the city by the Sunni militants to date.

The militants' push comes after the Islamic State was dealt a major blow earlier this month, when Iraqi troops routed the group from Tikrit, Saddam Hussein's hometown.

Wednesday's fighting could also further threaten Ramadi, 115 kilometers (70 miles) west of Baghdad. Nearly a decade ago, Ramadi was one of the strongholds of the insurgency in the U.S.-led war in Iraq. It now is mostly held by Iraqi government forces, although militants control some parts of it, mainly on the outskirts.

In a dawn advance, IS extremists seized the villages of Sjariyah, Albu-Ghanim and Soufiya, which had also been under government control until now, and residents said they had to flee their homes. Fighting was also taking place on the eastern edges of Ramadi, about 2 kilometers (a mile) from a government building, they added.

In Soufiya, the militants bombed a police station and took over a power plant. The residents, who spoke on condition of anonymity because they feared for their safety, said airstrikes were trying to back up Iraqi troops. Iraqi security officials could not immediately be reached for comment.

Around noon Wednesday, the militants opened another front with government troops on three other villages to the northeast of Ramadi, the residents added.

An Iraqi intelligence official said the militants were preparing to launch another offensive from the western side of the city, describing the situation as "critical."

The IS was also trying to take control of the main highway that goes through Ramadi to cut off supplies, the official said, speaking on condition of anonymity because he was not authorized to talk to the media.

Defense Ministry spokesman Brig. Gen. Tahseen Ibrahim acknowledged that Islamic State militants "gained a foothold in some areas" in Anbar. But he said reinforcements were sent to the province and that airstrikes from the U.S.-led coalition were supporting Iraqi forces.

"The situation is under control, and the standoff will be resolved in the coming hours," Ibrahim told The Associated Press. He added, however, that most of the villagers in the area had fled from their homes amid the fighting.

Hundreds of U.S. and coalition forces have been training Iraqi troops at Anbar's Ain Al-Asad air base, about 110 kilometers (68 miles) west of Ramadi, which came under IS attack in mid-February. The attack, which involved a suicide bomber, was repelled.

The Anbar fighting coincides with Iraqi Prime Minister Haider al-Abadi's visit to Washington where he met Tuesday with President Barack Obama and appealed for greater support from the coalition carrying out airstrikes against the IS militants, who have also captured large areas in neighboring Syria. While Obama has pledged another $200 million in humanitarian aid, he made no mention of any further military support.

In an interview with a group of U.S. reporters, al-Abadi made no mention of the events in Ramadi. He spoke optimistically of gaining Sunni tribal fighter participation in the government's offensive, saying about 5,000 tribal fighters in Anbar had signed up and received light weapons. "There is a problem because they are asking for more advanced weapons, which to be honest with you we don't possess," he said.

Those Sunnis are working "hand-in-hand" with Iraqi security forces, al-Abadi said. As an example of this cooperation, he said he recently visited Habbaniya in Anbar province and walked among 1,500 armed Sunni tribal fighters.

"I felt safe," he said. "That's how much the situation has changed in the country. That says a lot about the situation in Anbar," he said.

Ramadi and Fallujah were major strongholds for al-Qaida insurgents during the eight-year U.S.-led invasion, and fighting in Anbar was especially costly for Americans there. A lasting image of the war was the bodies of U.S. contractors hanging from a bridge in Fallujah in March 2004. The six-week fight in November 2004 to retake Fallujah was an iconic moment for the Marines — with nearly 100 Americans killed in battle and hundreds more injured.

Many of the insurgents were forced to flee Iraq or go into hiding in the latter years of the invasion.

In late 2013, however, militants of the Islamic State group used the Syrian civil war to their advantage and began to push back into Iraq through Anbar province. They capitalized on resentment toward the Shiite-led government in Baghdad to secure their position among predominantly Sunni residents. In January 2014, Fallujah was the first major Iraqi city seized by the militant group, and it has been making slow, but steady progress in the province ever since.

The seizure of about a third of Iraq by the Islamic State has pushed the country into its worst crisis since the 2011 withdrawal of U.S. troops.

Al-Abadi said Iraqi forces will follow their victory in Tikrit with campaigns against Islamic State in the oil town of Beiji and western Anbar province. He said a counteroffensive against the northern town of Mosul would not come before the Muslim holy month of Ramadan, which begins in mid-June.

The U.S. Central Command said the international coalition carried out 23 airstrikes on militants in Iraq and Syria since Tuesday. Of those, 17 were in Iraq, including three near Ramadi on tactical units an armored personnel carrier, two near Fallujah, and nine near Beiji, it said.

In addition to the clashes in Anbar province, a series of militant attacks in and around Baghdad killed at least 43 people in the past two days.

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Associated Press writers Sameer N. Yacoub, Qassim Abdul-Zahra and Vivian Salama in Baghdad and National Security writer Robert Burns in Washington contributed to this report.