Islamic State extremists unleashed a wave of suicide attacks targeting the Iraqi army in western Anbar province, killing at least 17 troops, an Iraqi military spokesman said Wednesday, as the militants prepared for a defense of Ramadi.

The attacks came just hours after the Iraqi government on Tuesday announced the start of a wide-scale operation to recapture areas under the control of ISIS in Anbar.

Brig. Gen Saad Maan Ibrahim, the spokesman for the Joint Military Command, told The Associated Press on Wednesday that the attacks took place outside the Islamic State-held city of Fallujah late the previous night.

The militants struck near a water control station and a lock system on a canal between Lake Tharthar and the Euphrates River where army forces have been deployed for the Anbar offensive, he said.

Ibrahim added that the Islamic State extremists used a sandstorm that engulfed most of Iraq on Tuesday night to launch the deadly wave of bombings. He said it was not clear how many suicide attackers were involved in the bombings but they hit the military from multiple directions.

Last month, the water station near Fallujah fell into the hands of ISIS militants — following attacks that also included multiple suicide bombings and that killed a general commanding the 1st Division and a dozen other officers and soldiers.

Iraqi government forces recaptured the station a few days later. Fallujah lies to the east of the Anbar provincial capital of Ramadi, which was captured by ISIS militants nearly two weeks ago in what was a major, humiliating defeat for Iraqi troops at the hands of the extremists.

Col. Steve Warren, a Pentagon spokesman, said ISIS was busy Wednesday preparing to defend the city.

“They are constructing berms, planting IEDs, attempting to flow supplies and equipment into Ramadi,” he told reporters.

Warren said Iraqi forces are positioned south, east and northeast of the city at the moment but no Iraqi forces or Shia militias have entered Ramadi’s city limits.

The Iraqi operation to retake Anbar, which is said to be backed by Shiite militias and Sunni pro-government fighters, is deemed critical in regaining momentum in the fight against the Islamic State.

ISIS captured Ramadi in Iraq and the Syrian ancient town of Palmyra earlier this month, showing that it is able to advance in both countries despite months of U.S.-led airstrikes.

Syria's foreign minister said Wednesday that his government is not pinning any hopes on the U.S.-led coalition striking at Islamic State group militants in his country.

At a press conference in Damascus, Walid al-Moallem said the coalition was active in preventing the Kurdish town of Kobani from falling into ISIS' hands last year but that this support seems to have "evaporated" after that.

The United States did nothing to prevent the ancient town of Palmyra in Syria or the province of Anbar in Iraq from falling into ISIS hands, he said.

"We're not pinning any hopes on that alliance and anyone who does is living an illusion," al-Moallem added.

Al-Moallem also said Iraq and Syria were fighting the same battle but added that security coordination between their two armies "has not reached the desired levels."

Also Wednesday, Syrian activists said the Islamic State group released two elderly Christian women who had been held along with dozens of others since February in northeastern Syria.

At the time, ISIS kidnapped more than 220 Assyrian Christians after overrunning several farming communities on the southern bank of the Khabur River in Hassakeh province.

The two women, who are 70 and 75 years old, were released on Tuesday and have now reached the northwestern city of Hassakeh, said Osama Edwards, director of the Assyrian Network for Human Rights.

Another activist group, the Syrian Observatory for Human Rights, said the two were likely released because of their poor health. Some of the captives had been released previously.

Edwards said the Islamic State is still holding 210 Assyrian Christians and is demanding $100,000 for each hostage.

Fox News’ Lucas Tomlinson and The Associated Press contributed to this report.