Canada will buy up to 16 spy planes from Boeing to replace an aging fleet and counter adversaries' increasingly stealthy and lethal capabilities near its coasts and overseas, officials said Wednesday.

The P-8A Poseidon aircraft -- which are used by the powerful Five Eyes intelligence alliance, to which Canada belongs with Australia, the United States, Britain and New Zealand -- will cost Can$10.4 billion (US$7.7 billion).

They are expected to be delivered starting in 2026 and become fully operational by 2033, replacing Canada's current CP-140 Aurora maritime patrol aircraft, which have been in service for more than 40 years and are due to be retired in 2030.

Defense Minister Bill Blair told a news conference the Aurora has "done its job well."

But, he added, "adversaries have been deploying increasingly sophisticated, stealthy and lethal capabilities and therefore the Aurora must be replaced" to meet those threats to Canada and its NATO allies.

The new planes, he said, will be tasked with detecting illegal fishing, drug trafficking, and polluters "along the longest coastline in the world," as well as hunting for submarines and ships in the Arctic and in overseas missions.