OTTAWA -- NATO Secretary General Jens Stoltenberg is making his first visit to Canada this week, just as the House of Commons is about to have another heated debate on the military mission in Iraq.

Stephen Harper is set to meet with Stoltenberg on Monday, and the prime minister's office says the security threat posed by the Islamic State of Iraq and the Levant (ISIL) will be a major topic of conversation.

Harper is set to put to the House of Commons this week a motion to expand and extend the mission to combat ISIL.

The NDP has already signalled its disapproval of the mission that is not led by the UN or NATO, while the Liberal position on a longer and broader mission is not yet clear.

A source close to the meeting says Harper and Stoltenberg will also discuss the evolving situation in Ukraine and rising tensions with Russia, an issue occupying much of the NATO chief's time.

On Sunday, NATO's supreme allied commander Gen. Philip Breedlove told a news conference that the west should consider sending defensive weapons into Ukraine.