A group of Calgary imams is marking the first line of defense at the foot of the Rocky Mountains against the Islamic State group's recruitment of Canadians as fighters.

Several imams issued a religious edict against IS jihadists last month, denouncing its threats against Canada and its online recruitment after dozens of Canadians -- mostly from Calgary -- traveled to Syria to join their cause.

The U.N. peace envoy for Syria wants to kickstart stalled negotiations to end the country's four-year conflict by hosting separate talks with rival sides next month, a spokesman said Tuesday.

Staffan de Mistura will begin "in-depth separate consultations... with Syrian stakeholders as well as with the regional and international actors in order to take stock of their views," U.N. spokesman Ahmad Fawzi told reporters.

Jihadists from the Islamic State group have lost ground to Palestinian fighters in Syria's Yarmuk camp, Palestinian officials and a resident said on Tuesday.

U.N. officials in Syria said, meanwhile, they were discussing ways of getting humanitarian aid into the camp and helping residents who have fled Yarmuk.

British police on Tuesday charged a 36-year-old man with the murder in London of an imam who was a critic of Syrian President Bashar Assad.

London's Metropolitan Police charged Leslie Cooper, 36, with the murder of Abdul Hadi Arwani after receiving authorization from the Crown Prosecution Service, the public prosecutor said in a statement.

Eyewitness accounts and evidence collected from northwestern Syria "strongly" suggest regime forces dropped toxic chemicals on civilians several times last month, Human Rights Watch said on Tuesday.

A high-ranking Syrian security official denied the claim, saying the accusations were "lies the insurgents say when they incur losses."

Servicemen taken hostage by the al-Qaida-affiliate al-Nusra Front are expected to be released within 10 days after negotiations with the group reached a breakthrough, al-Mustaqbal newspaper reported on Tuesday.

“Negotiations passed a long way and reached an advanced level,” a concerned source told the daily.

Australia said Tuesday 330 troops were heading to Iraq for two years to train local soldiers fighting jihadists including the Islamic State group, joining an aerial and special forces contingent in the region.

Prime Minister Tony Abbott said the troops would be deployed from Wednesday and operate from the massive Taji base complex north of Baghdad alongside 100 soldiers from New Zealand.

Lebanese businessmen in Saudi Arabia, Kuwait, the United Arab Emirates and Qatar are planning to visit Gulf countries to announce their support for the Saudi-led coalition against Huthi rebels in Yemen, al-Liwaa daily reported on Tuesday.

The tour of the Lebanese expatriates is aimed at throwing their weight behind the decision of Saudi King Salman last month to carry out air strikes against the Shiite rebels to defend Yemeni President Abedrabbo Mansur Hadi's government, said the report.

The Islamic State group has lost control of "25 to 30" percent of the territory it holds in Iraq after coalition air strikes and an Iraqi offensive, the Pentagon said Monday.

The radical group took control of large swathes of the north and western parts of the country months ago after an offensive and the collapse of Iraqi military units.

Al-Qaida's Syrian affiliate led a fierce assault on an intelligence base in Aleppo city Monday night after regime attacks on civilian infrastructure in the city forced rebels to shut schools.

Along with other Islamist militants, the al-Nusra Front set off a large tunnel explosion near the air force intelligence headquarters in the west of the northern city.