OTTAWA - New Democrats are refusing to back Prime Minister Stephen Harper's decision to send special forces commandos into northern Iraq.

NDP Leader Tom Mulcair says it's the only responsible position to take, given the government's refusal to provide details of the deployment or to allow parliamentarians to vote on the matter.

Harper has confirmed that Canada has sent 69 special forces commandos to Iraq as part of a counter-terrorism campaign against the extremist al-Qaida splinter group known as the Islamic State of Iraq and the Levant, or ISIL.

He maintains the deployment, which is to be reviewed within 30 days, is not a combat mission, that the commandos will only advise and assist Iraqi forces and Kurdish fighters who are resisting ISIL forces in northern Iraq.

Liberal Leader Justin Trudeau is backing the deployment.

But Mulcair says he can't support the mission when the government refuses even to reveal precisely when the commandos arrived in Iraq or when the 30 days will be up.