Air strikes in northern Iraq on Thursday killed the top aide of jihadist Islamic State (IS) chief Abu Bakr al-Baghdadi, the country's ranking army officer said.

"Iraqi warplanes carried out a security operation today, resulting in the killing of... Abu Hajr al-Suri," General Babaker Zebari told AFP.

Zebari said the strikes in Nineveh province were "based on accurate intelligence information," and that the target was destroyed.

It was not possible to independently confirm Suri's death.

The area where the strikes were carried out, located between Mosul and Tal Afar, is outside government control, posing a major challenge to verifying Suri's death.

IS-led militants launched a major offensive in June, overrunning Iraq's second city Mosul and then sweeping through much of the country's Sunni Arab heartland.

The group also holds significant territory in neighbouring Syria, and has declared a cross-border Islamic "caliphate" in which it has carried out atrocities that have shocked the world.

IS launched a renewed push in Iraq last month that drove Kurdish forces back toward the capital of their autonomous northern region, sparking a campaign of US air strikes that have helped them regain some ground.

The federal government won its first major military success of the conflict on Sunday, when Iraqi forces, Shiite militiamen and Kurdish fighters broke a months-long jihadist siege of the town of Amerli and surrounding areas.

US fears Syrian chemical weapons falling to extremists: Power
United Nations, United States (AFP) Sept 04, 2014 - The United States expressed concern Thursday that undeclared Syrian chemical weapons could fall into the hands of Islamic extremists.

US Ambassador Samantha Power raised the concerns as a joint UN and Organization for the Prohibition of Chemical Weapons mission winds up an drive to eliminate Syria's chemical arsenal.

The mission is supposed to formally conclude its work by September 30, but its chief Sigrid Kaag said there were still "discrepancies and questions" related to Syria's weapons declarations.

"The international community must continue to press for a resolution of all discrepancies and omissions," said Power.

"The US is concerned about all discrepancies and also the potential that there are real omissions in the declaration," she added.

Power said the Security Council, currently presided by the United States, "intends to stay very much on top of this."

"Extremist groups have terrorized everyone they come into contact with in Syria and Iraq and these weapons stocks, if there are any left, could fall into their hands," she said.

The United States has launched an air campaign against Islamic State militants as they have swept through large parts of Iraq from strongholds in Syria.

Power also recalled that the Syrian regime had carried out chemical weapons attacks itself, particularly on August 21 2013 in a Damascus suburb.

Kaag, delivering her last report to the Security Council as the mission's chief, said Damascus had presented "four amendments" to its weapons declaration, and that there had been "constructive" discussions on certain discrepancies, including the volume of toxic chemicals declared.

A total of 1,300 tonnes of chemical agents have been removed from Syria and subsequently destroyed at sea.

Turkey arrests 19 jihadists in border province
Istanbul (AFP) Sept 04, 2014 - Turkey has arrested 19 militants affiliated with the Islamic State in its southern province of Gaziantep bordering Syria, its governor said on Thursday.

Gaziantep province governor Erdal Ata vehemently denied claims that the region was being used as a rear base for IS militants, saying Turkey was doing all it can to arrest or deport suspected IS members.

"Police and the security forces are showing all the necessary sensitivity on this issue," he was quoted as saying by the private Dogan news agency.

"The trial of 19 suspects caught so far has been continuing and they are under arrest," he said.

The governor also said police had caught suspected IS-linked jihadists coming from Europe or Caucasus, carrying backpacks, at the Gaziantep airport or at the border.

Ata said those believed to have committed crimes would be put on trial while suspected IS sympathisers would be deported.

He however strongly denied the claims that Gaziantep province hosted a camp of IS militants after some pictures purporting to show such a facility circulated in media outlets last week.

Ata said he himself scrutinised the pictures, implying they were fakes.

"We don't have such a camp in our province and its presence... is out of the question," he said.

Turkey has been criticised by some commentators for indirectly encouraging the formation of the Islamic State with its wholehearted support of Islamist elements within the Syrian rebellion against President Bashar al-Assad.

Ankara denies that its strategy has backfired, but many critics say it could have done far more, sooner to tighten porous borders and stop the flow of militants into Syria.

After a lightning advance, IS militants now control swathes of Iraq and much of northern Syria on the Turkish border.

Turkey now sees itself a victim of the IS with Islamist militants holding 49 Turks hostage, including diplomats and children, abducted from the Turkish consulate in Mosul in Iraq on June 11.

Turkish officials are now refraining from giving almost any comments about the situation in Iraq and Syria, in apparent fear of aggravating the hostage situation.

The concerns come as President Recep Tayyip Erdogan and US President Barack Obama are expected to hold their first face-to-face meeting for the past year and a half, on the sidelines of the NATO summit in Wales.