Prime Minister Stephen Harper says Canada is considering bolstering its long-term military presence in Eastern Europe to counter the long-term threat posed by Russia.

Harper, speaking in Warsaw on Wednesday after a meeting with Polish Prime Minister Donald Tusk, stressed no decisions had been taken.

But he says he welcomes U.S. President Barack Obama's announcement Tuesday in Warsaw to bolster U.S. military contributions to the region, and to seek $1 billion from Congress.

Harper also announced Canada will modestly bolster its military forces in the greater region by deploying a contingent of approximately 75 soldiers to Latvia.

"We are very much looking at options for additional presence going forward but no decisions have been taken," Harper said.

Canada already has 50 troops on training manoeuvres in Poland.

PM slams Russia's 'aggressive behaviour'

Harper began his visit to Eastern Europe today by heaping more criticism on Russian actions in Ukraine.

After meeting with Poland's Tusk, Harper said Russia's "aggressive behaviour" requires a sustained and co-ordinated response.

Tusk said he welcomed Canada's additional contribution to military resources in the region. Poland has been pushing hard for increased NATO presence in Eastern Europe.

Harper said the actions of Russian President Vladimir Putin pose a long-term threat to the region that won't disappear any time soon.

"I do believe that what is occurring in Russia under President Putin is a serious development with serious long-term consequences that I don't believe we should think for a moment will disappear in the near future," Harper said.

Harper has labelled Putin a threat to world peace after Russia annexed the Crimean Peninsula, and for instigating the continuing unrest in eastern Ukraine.

Military co-operation 

Harper also said he was pleased to see an increase in military co-operation between Poland and Canada, including a joint training exercise now underway.

Harper also affirmed the continued sanctions against members of Putin's government.

The prime minister also used the occasion to congratulate Poland on the 25th anniversary of the nation's emergence from communism. He planned to join Obama and other world leaders in Warsaw later today to mark the anniversary.

Harper will also return to Ukraine on Saturday to attend the swearing in of the country's new president-elect, Petro Poroshenko.

The visit was announced on Harper's aircraft after it left Ottawa on Tuesday.

Harper's itinerary also includes a G7 summit in Belgium and the 70th anniversary ceremonies of the Normandy invasion in France.