Ottawa has started to make payments for key components for 14 additional U.S.-built F-35s, even as the Carney government has been reviewing future fighter-jet purchases in the context of trade tensions with Washington, sources have told CBC News.

The money for these 14 aircraft is in addition to the contract for a first order of 16 F-35s, which will start being delivered to the Canadian Armed Forces at the end of the year.

According to sources, the new expenses are related to the purchase of so-called “long-lead items,” which are parts that must be ordered well in advance of the delivery of a fully assembled aircraft.

Canada had to make these expenditures to maintain its place in the long-term delivery schedule and avoid being replaced by other buyers in the queue, sources said.