US air strikes against Islamist extremists in Syria killed two children by mistake, officials said Thursday, marking the first time the American military acknowledged inflicting civilian casualties in the war.

"We regret the unintentional loss of lives," Lieutenant General James Terry, head of the US-led air campaign against the Islamic State group, said in a statement, citing the results of an investigation.

The air strikes on November 5-6 last year were targeting members of the Khorasan group, an offshoot of Al-Qaeda, in Harim City, according to the inquiry's conclusions.

"The strikes were designed to destroy targets utilized by Khorasan group-affiliated extremists to meet and manufacture explosives," the report said.

But the bombing killed two children -- including the daughter of a militant -- and caused "minor injuries" to two civilian workers who lived near the buildings that were targeted, it said.

In assessments prior to the air raid, there were no reports that children could be in the area, the probe concluded.

The air strikes were carried out in accordance with extensive rules designed to avoid civilian deaths and the targets were deemed "valid military targets," it said.

The report found no wrongdoing or negligence by military forces overseeing or carrying out the strikes.

Human rights groups have alleged dozens of civilians have been killed in various air strikes on extremists in Syria and Iraq.

But Pentagon officials had maintained previously that they could not confirm with certainty that any civilians had been inadvertently killed in the US-led air campaign in Iraq and Syria, despite more than 4,000 bombing raids.

The air war was launched in Iraq in August and extended to Syria in September.

Military investigators had reviewed an account of the strike from the Syrian Network for Human Rights, statements from Syrian "civil society contacts" to the State Department and video from the strike, the inquiry report said.

"It is important to note that the current environment in Syria and Iraq makes investigating these allegations extremely challenging," Pentagon spokeswoman Commander Elissa Smith said.

"Traditional investigative methods, such as interviewing witnesses and examining the site, are not typically available," she said.

"However, we also consider information provided to us by other US government departments and agencies such as human rights documentation groups, and we seek to investigate as thoroughly as possible given the limitations."

US defense officials had previously said the same strikes in Syria in November 2014 had killed a French bombmaker, David Drugeon, who was portrayed as a key figure in the Khorasan group.

Canadians have 'no legitimate reason' for joining extremists: Harper
Montreal (AFP) May 21, 2015 - Prime Minister Stephen Harper blasted would-be Canadian jihadists Thursday, saying there is "no legitimate reason" in a liberal democracy to join any extremist group.

Harper announced fresh funding for border and federal police agencies, during a visit to the Montreal airport where days earlier 10 teenagers who allegedly hoped to join the Islamic State group were arrested boarding a flight to the Middle East.

"We have a great country here," Harper said. "We have a country unparalleled in terms of its freedom, democracy, its openness and its tolerance.

"There is no legitimate reason of any kind in this country for someone to become a violent jihadist or become a terrorist or join any group that is involved and advocates that kind of activity.

"It's totally unacceptable to Canada and Canadians, and unacceptable to this government."

Harper also pledged Can$150.36 million (US$123 million) in funding over five years and Can$46.79 million per year thereafter to boost the RCMP's "investigative capacities," as well as Can$1.1 million annually to help the Canada Border Services Agency better "target high risk travellers."

The Islamic State group is known for its brutality in territory it controls in Syria and Iraq. The group's radical ideology has inspired thousands of people to join it or try to send support.

Canada in particular has been concerned over the increasing number of youths from the country who have tried to join the group.

According to the RCMP, more than 100 Canadians have joined the ranks of the Islamic State group in Syria and Iraq.

The number of jihadists' departures from Canada has ramped up with at least a dozen men and women in their teens or twenties having attempted to reach Syria since January, including a woman who had taken an online religious course only to be recruited by the teacher to become an IS fighter's bride.

Several other jihadists attended the same high school in Montreal where a controversial imam, who years ago successfully challenged his detention without trial over suspicions that he was an Al-Qaeda sleeper, taught religious studies.