China has executed four Canadians, according to Ottawa's foreign affairs minister, who condemned Beijing for not heeding their calls for leniency.

Canada said on Wednesday that China had executed four Canadian citizens on drugs smuggling charges earlier this year, and strongly condemned Beijing's use of the death penalty. Foreign Minister Melanie Joly told reporters that all four had been dual citizens and said Ottawa would ask for leniency for other Canadians facing the same fate.

Four Canadians were executed in China on drug-related charges earlier this year, Canadian authorities have confirmed. All of them were dual citizens, and their identities have been withheld upon the request of their families,