An air strike in the Iraqi town of Hawijah completely levelled one of the Islamic State group's largest car bomb factories, causing heavy casualties and extensive destruction, officials said.
The blast caused by the strike and the destruction of explosive material was heard as far as Kirkuk, a city under Kurdish control that lies 55 kilometres (34 miles) away.
Iraqi officials said the strike was carried out by a US-led coalition, which has defended its 10-month air campaign against IS despite a number of recent advances by the jihadists in Iraq and Syria.
The facility, which included tanks, Humvees and large quantities of explosives, was "the biggest factory in Iraq and Syria", an Iraqi colonel said.
Mohammed Khalil al-Juburi, the deputy head of the Kirkuk province security committee, confirmed details of the attack, which took place early on Wednesday.
Both said a large number of IS militants and civilians were killed and wounded in the strike on the edge of Hawijah but neither gave exact figures.
The coalition issued a statement listing its air strikes in Iraq and Syria over a period of 24 hours straddling Tuesday and Wednesday.
It mentions that a "VBIED (vehicle-born improvised explosive device) facility" was struck in the Hawijah area but does not provide any details.
Mobile phone photos obtained by AFP that were said to show the site of the explosion picture damage on a massive scale.
They show a huge field of debris -- cinderblocks, metal roofing, the twisted remains of vehicles -- that stretches as far as the eye can see.
IS has made vehicle bombs, in some cases huge trucks packed with explosives, a central feature of its military tactics
Hawijah, located 225 kilometres (140 miles) north of Baghdad, is an IS stronghold that lies at the crossroads of several fronts in Iraq.
Iraqi government and allied forces have been involved in a vast operation aimed at cutting off supply lines between the provinces of IS' self-proclaimed caliphate.
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- 'Water war' -
One of the immediate goals is to isolate jihadists in Anbar, a vast western province whose capital Ramadi government forces lost on May 17 in a bruising setback.
Since taking the city, IS has closed one section of a diversion dam in a move officials warned would lower water levels in one branch of the Euphrates and make it easier for the jihadists to manoeuver and launch attacks.
"Daesh is now waging a filthy water war," said Sabah Karhout, the head of Anbar's provincial council, using an Arabic acronym for IS.
"Cutting the water is the worst crime they could commit. It will force children, women and elderly people to flee and allow them to move in to launch attacks," he said.
Arkan Khalaf al-Tarmuz, another provincial council member, said: "Daesh may not have enough fighters to face us in a conventional battle right now.
"So they are using water as a weapon to weaken areas where there are military bases."
US Deputy Security of State Anthony Blinken told France Inter radio that 10,000 IS members had been killed since the start of a nine-month-old US-led air campaign in Iraq and Syria.
IS has repeatedly sought to control Iraq's dams, in some cases reducing the water flow to areas under government control or flooding land to impede military operations.
"In the arid lands where the Islamic State fights, control of water is the ultimate weapon of terror," the Soufan Group intelligence consultancy said in a briefing note Wednesday.
At a Paris meeting that ended on Tuesday, Western powers and other members of the 60-nation coalition vowed more support for Iraqi Prime Minister Haider al-Abadi's efforts.
Abadi had said that IS's regained momentum was a sign of the international community's "failure" to provide adequate support.
But Washington, which continues to refuse to send combat troops back to Iraq, and the coalition insisted they had a "winning strategy" of air strikes combined with thousands of forces training and advising Iraqi forces.
"In Iraq right now we have the right strategy, a combination of air strikes, training and effective global partners," Blinken said at the meeting.