Canada's recent concessions to Trump appear to have yielded, to date, little result.
Officials have not disclosed what substances they suspect may have been involved.
The US president said he will send weapons to NATO, which he said would pay and then give the weapons to Ukraine.
Iran denies seeking to develop nuclear weapons and says its enrichment of uranium is for peaceful purposes.
Both acknowledged that it was a real possibility, but both had a deep worry beyond that.
A blanket 25% tariff has already been imposed on some Canadian goods.
The senior agent was shot in a car park in broad daylight on Thursday morning, CCTV shows.
PM says migrant return scheme to begin "in weeks".
Female students were stripped naked after blood stains were found on a toilet wall.
