A double-decker bus crashed into a train at a crossing in a suburban neighborhood of Canada's capital Wednesday, killing at least six people and leaving scores injured, authorities said.

Thirty people were hurt, with 10 in serious condition, officials told reporters following the morning commute collision.

Canada will resettle up to 5,000 mostly Iraqi and Iranian refugees now in Turkey, Immigration Minister Jason Kenney announced Tuesday.

"With escalating violence in the region, more people are seeking protection in Turkey, and our commitment to resettle 5,000 mostly Iraqi and Iranian refugees in Canada will help Turkey deal with this growing pressure," Kenney said in a statement.

The science journal Nature called on the Canadian government in an online editorial Friday to "set its scientists free" and allow them to speak about their research.

"It is time for the Canadian government to set its scientists free," Nature said in a rebuke of a "gradual tightening of media protocols for federal scientists" since Prime Minister Stephen Harper's Conservatives won power in 2006.

Canada has expelled four Russian diplomats following the arrest last weekend of a Canadian soldier charged with leaking secrets to a foreign entity, a newspaper reported Friday.

Canada's Globe and Mail said the four diplomats had been removed from the list of envoys officially recognized by Canada, while the CBC news service said at least some of them had left the country over the spying case.