British Prime Minister David Cameron was preparing Thursday for a key vote on joining air strikes in Iraq as police arrested nine people, including a notorious radical preacher, accused of links to Islamist extremism.

Cameron was meeting ministers after returning from the U.N. General Assembly in New York, where he announced that parliament would vote Friday on British planes joining U.S.-led strikes against the Islamic State (IS) group in Iraq.

French Muslims were on Thursday called to rally against the "barbaric" beheading of a hostage by Algerian jihadists with links to radical Islamic State militants.

Dalil Boubakeur, the president of the French Council of the Muslim Faith (CFCM) -- an official representative for the country's estimated five million Muslims -- called for the gathering at the Paris Mosque on Friday afternoon.

Jihadists linked to the Islamic State group beheaded a Frenchman abducted in Algeria in a video posted online Wednesday, after Paris rejected their demand to halt air strikes in Iraq.

President Francois Hollande condemned the "cruel and cowardly" murder of Herve Gourdel and said it would only strengthen France's resolve to pursue its air war against the Islamic State group.

France's interior minister on Wednesday announced a probe into a series of blunders that saw three suspected jihadists waltz out of a French airport after being transferred from Turkish custody.

Authorities were left red-faced after an announcement they had arrested the three men at a Paris airport turned out to be false.

An emergency recall of Britain's parliament to decide whether to join U.S.-led air strikes against the Islamic State group in Iraq could take place as early as Friday, Britain's press reported.

Prime Minister David Cameron is due to meet Iraqi counterpart Haidar Al-Abadi in New York on Wednesday, on the sidelines of a U.N. General Assembly, and it is expected that there will be a formal request for Britain to take part in the strikes.

A corruption and influence-peddling investigation launched in July against former French president Nicolas Sarkozy has been suspended, days after he dramatically announced a political comeback.

The Paris appeals court decided Tuesday to freeze the probe pending a study of a request by Sarkozy to have it dismissed, a source close to the enquiry told Agence France Presse on Wednesday. The suspension could last several months.

The brother-in-law of Mohamed Merah, the Al-Qaida-inspired gunman who went on a killing spree in 2012 that shocked France, was arrested at a Paris airport Tuesday on suspicion of having joined jihadists in Syria.

The man -- the husband of Merah's sister Souad, who herself is believed to be in Algeria -- was detained at Orly airport near Paris along with two other people, interior ministry sources said.

British Prime Minister David Cameron is to hold talks with Iran's President Hassan Rouhani over unrest in Iraq and Syria, officials said Tuesday, the first meeting between the country's leaders since the 1979 Islamic Revolution.

The talks at the U.N. General Assembly in New York come as Western powers seek to build support for the fight against the Islamic State (IS) jihadist group, which holds swathes of territory in Iraq and Syria and has beheaded two U.S. journalists plus a British aid worker.

Paris will not make any concessions to jihadists who have threatened to kill a French hostage in Algeria, President Francois Hollande said Tuesday.

"As grave as this situation is, we will not give into any blackmail, any pressure, any ultimatum no matter how odious, how despicable," he said, vowing to continued support for Iraqi authorities battling jihadists.

Foreign Minister Julie Bishop on Tuesday said Canberra was treating as genuine a call by the Islamic State group for Muslims to indiscriminately kill Australians, issued after anti-terrorism raids foiled an alleged abduction plot.

The militants on Monday released a statement urging the deaths of citizens of all countries taking part in the U.S.-led coalition against the jihadists. Australia was mentioned, along with the United States, Canada and France.