BRUSSELS—Canada will serve as one of four lead nations for a North Atlantic Treaty Organization deterrent force in Eastern Europe, Canadian Defense Minister Harjit Sajjan said Thursday.

NATO approved the force last February for Poland and the three Baltic States. The U.S., the U.K. and Germany had each agreed to lead three battalions or battle groups, but the alliance struggled to find a nation to lead the fourth battalion after Norway and Denmark declined.

Mr. Sajjan, in a telephone interview, said that Canada had agreed to lead the fourth nation. Details of the deployment, including how many troops Canada will send are to be announced at next week’s NATO summit in Warsaw.

NATO diplomats have said Canadian forces are expected to go to Latvia while the U.S. battalion goes to Poland, the Germans to Lithuania and the U.K. in Estonia. Other nations, including Denmark and France, are contributing smaller numbers of forces, officials have said.

“NATO was created for deterrence, and we need to make sure it is properly resourced,” Mr. Sajjan said. “Canada is going to be a strong partner and be part of that.”