OTTAWA — Prime Minister Stephen Harper says Canada will send CF-18 fighter jets to help enforce a no-fly zone over Libya, despite Moammar Gadhafi's ceasefire declaration.

Canada's six war planes will join an international effort authorized by the United Nations Security Council on Thursday night.

"If Col. Gadhafi does not comply with this Security Council resolution, Canadian armed forces working with other like-minded nations will enforce this resolution," Harper said.

The jets were to leave Canadian Forces Base Bagotville in Quebec as early as Friday afternoon for an air base in Italy. About 150 support staff will be joining them.

Canada's fighter planes last took part in such a mission in 1999 when they joined the NATO bombardment of the former Yugoslavia to stop ethnic violence against Kosovo Albanians.

Lt.-Gen. Andre Deschamps, the head of the Air Force, said there were parallels with the Kosovo mission because both involved protecting citizens who were being mistreated by their governments.

Once the planes arrived in theatre, they would rally up with allied forces and hammer out specific rules of engagement that would conform to the UN resolution, he said.

"The no-fly zone will involve certain risks because the situation is still somewhat unstable in Libya. So it will depend on what the Libyan government actually does," said Deschamps.

Britain and France have already said they will send war planes to the mission.

Harper spoke by phone Friday with British Prime Minister David Cameron.

However, in the face of international resolve, Libya declared a ceasefire Friday and pledged to end military action.

Harper said that was an encouraging development, but it does not change the fact that military resources must still be deployed.

"We are encouraged by late-breaking news that in response to the threat of military action the Libyan regime has declared a ceasefire. However, for that threat to remain credible, adequate military forces must be in place. Our deployment will therefore proceed."

Harper said he had advised Canada's opposition leaders of the decision.

The prime minister said the government would consult Parliament next week and would seek its formal approval if the deployment lasts more than three months.

Liberal Leader Michael Ignatieff said his party supports the decision to send planes, but not ground troops in the event military action escalates.

"The prime minister has assured me that this does not involve ground combat operations," Ignatieff said.

"If combat operations are ongoing it will require formal parliamentary approval and I made that point clear to the prime minister."

Ignatieff noted that Canada's failure last fall to win a temporary two-year term on the Security Council meant it was not at the table when the UN resolution was finally passed on Thursday.

"We could have been at the centre of the action. But now we're taking part and we support that as an emergency measure," said Ignatieff.

"My party has called for about 10 days now, two weeks now, for a no-fly zone. We believe that the international community and Canada has a responsibility to protect civilians when they're attacked."

Canada worked with its allies to push for the UN resolution, Harper said.

"One either believes in freedom or one just says one just believes in freedom. The Libyan people have shown by their sacrifice that they believe in it. Assisting them is a moral obligation upon those of us who profess this great ideal."

Harper said the action was necessary to prevent "further massacres."

Britain said Friday it would send Typhoon and Tornado fighter jets to air bases in the region.

Britain, France and NATO were holding emergency planning meetings Friday, but there were no details on what the U.S. role would be in the military action.