An Egyptian police officer was shot dead north of Cairo on Thursday while on a mission to arrest militants suspected of assassinating a senior security official, the interior ministry said.

Captain Ahmed Samer Mahmoud was killed at dawn in an operation in the Nile Delta town of Qulubiya when a team of special forces exchanged gunfire with militants, the ministry said.

Authorities have arrested four female al-Qaida suspects in southeastern Yemen as they attempted to flee the scene of deadly clashes between police and jihadists, a security official said Thursday.

The women, three of them Saudis, were arrested Wednesday as they tried to flee a house in Shahr, in the extremist stronghold of Hadramawt province, the source said.

Saudi religious police arrested two young men offering a "free hug" to passers-by in the ultra-conservative Muslim kingdom's capital, local media reported Thursday.

The arrests were made in the main Tahlia Street where the two men were waving banners marked "Free Hug" in English, according to news website Sabq.org.

An al-Qaida front group fighting in Iraq and Syria has called for jihadist groups to join forces under its banner, according to an audio message posted Thursday on the Internet.

In remarks purportedly made by Abu Mohammed al-Adnani, the Islamic State of Iraq and the Levant (ISIL) spokesman said militant groups should close ranks against Syrian President Bashar Assad.

Syria's authorities have arrested Rajaa Nasser, a dissident whose National Coordination Committee for Democratic Change is tolerated by President Bashar Assad's regime, a party official said Thursday.

Top NCCDC official Nasser "was arrested on Wednesday" in the Baramkeh district in the heart of Damascus by a security patrol, party chief Hassan Abdel Azim told AFP.

Four British men have been killed fighting alongside Al-Qaida-linked fighters in Syria, it was reported Thursday, as fears rise of the growing threat from jihadists returning from the war.

Three of the men, all thought to be from London, were killed in August as their group attacked forces loyal to President Bashar Assad near Aleppo, according to The Times.

Pope Francis on Thursday said the Catholic Church will not accept a Middle East without Christians, who often find themselves forced to flee areas of conflict and unrest in the region.

"We will not resign ourselves to imagining a Middle East without Christians," he said after meeting with patriarchs from Syria, Iran and Iraq, before calling for "the universal right to lead a dignified life and freely practice one's own faith to be respected."

Divisions in rebel ranks and more committed loyalist fighters are helping the Syrian regime notch up military victories that would give it the upper hand at peace talks, analysts and rebels say.

The army's capture this week of the strategic town of Qara, north of Damascus, followed three days of fighting against Al-Nusra Front jihadists.

A bombing at a market north of Baghdad was the deadliest in violence that killed 41 people Thursday, as the year's death toll topped 5,800 amid a surge in unrest.

The flare-up has prompted Baghdad to appeal for international help in fighting the country's worst bloodshed since 2008, just months before its first general election in four years.

Israeli Prime Minister Benjamin Netanyahu on Thursday warned world powers negotiating with Iran that an anti-Israel speech by Iran's supreme leader gave fresh proof over why Tehran must not acquire a nuclear weapon.

Speaking to leaders of Russia's Jewish community on the second day of a visit to Moscow to campaign against an emerging world power deal with Iran, Netanyahu accused Supreme Leader Ayatollah Ali Khamenei of using the lexicon of the Nazi Holocaust.