NATO Secretary General Jens Stoltenberg is making his first visit to Canada this week, with the subject of how to address rising tensions with Russia likely to feature high on the agenda.

Prime Minister Stephen Harper met with Stoltenberg on Monday, and a Canadian source close to the meetings said the threat posed by the Islamic State in Iraq and Syria (ISIS) was to be a major topic of discussion.

There is no press conference scheduled.

Harper plans to ask the House of Commons to extend and expand Canada's military involvement this week.

But NATO has had no formal role to date in fighting ISIS. Russian President Vladmir Putin's recent moves, including mobilizing 45,000 northern troops for military exercises last week, have been the alliance's major preoccupation.

On Sunday, NATO's supreme allied commander Gen. Philip Breedlove told a news conference that the west should consider sending defensive weapons into Ukraine. The UN has said 6,000 people have died in the country over the past year.

The United States has been actively considering sending lethal defensive weapons to Ukraine to help that country defend itself against Russian-backed fighters. Germany has urged caution, warning that supplying Ukraine could escalate tensions.

Defence Minister Jason Kenney has dropped broad hints that Canada could be poised to provide Ukraine with more military assistance. He has said cabinet is considering whether Canada should join the U.S. and Britain in a military training mission to help Ukrainian troops.

Stoltenberg, a former Norwegian cabinet minister who took up the post last October, has warned that snap Russian military exercises and less communication between Russia and NATO could have dire consequences.

"It is important we keep the channels for military communication open to have as much transparency as possible to avoid misunderstandings and to make sure that incidents don't spiral and get out of control," Stoltenberg told the Guardian newspaper last week.

On the ISIS threat, NATO has not yet received an invitation from the Iraqi government to help with security force training. That task is currently being led by the U.S. at two camps in Iraq.