Women account for about one-fifth of extremists from Canada who head overseas, says the government's latest public report on terrorism.

In some cases women have taken their children to conflict zones, says the annual assessment of the terrorist threat.

The report issued Thursday says the participation of women in terrorist organizations is not new. However, there has been an increase in the number of women who have travelled or attempted to travel abroad to join the Islamic State of Iraq and the Levant.

Story continues below advertisement

The report says it is often unclear what roles are performed by women who travel to join extremist groups.

It notes the most common assumption is women travel abroad to marry terrorists, but some may occupy secondary roles within extremist groups, and in other cases appear to be training and taking part in combat.

Groups such as Boko Haram in North Africa are using female suicide bombers to cause mass casualties, the report adds. "Some of these women and girls were likely kidnapped and forced into the attacks, while others may be willing relatives of male fighters who have been killed."

As of the end of 2015, the federal government was aware of approximately 180 people abroad with a nexus to Canada who were suspected of engaging in terrorism-related activities, the report says. More than half were believed to be in Turkey, Iraq or Syria.

The government was also aware of a further 60 extremist travellers who had returned to Canada.

The figures are consistent with ones made public in February by CSIS director Michel Coulombe.

The report says the phenomenon of extremist travellers — including those abroad, those who return and those prevented from travelling — poses a range of security concerns for Canada.

Story continues below advertisement

Returning travellers may have "skills, experience and relationships developed abroad that could be used to recruit or inspire individuals in Canada," it says. They may also engage in terrorist financing, help others to travel or even plan attacks in Canada.

The principal terrorist threat to Canada continues to be violent extremists who could be inspired by groups like ISIL and al-Qaida to carry out an assault, the government says.

Jihadi sympathizer Aaron Driver was killed by police during a confrontation in Strathroy, Ont., earlier this month after a martyrdom video he made came to the attention of authorities.

The would-be target of Driver's thwarted attack remains unclear.