A Canadian teacher arrested in China for administrative reasons -- a case officially unrelated to the ongoing diplomatic row between Beijing and Ottawa -- has been freed, authorities said Friday.

Global Affairs Canada "confirms that a Canadian citizen, who was detained in China in December, was released and has now returned to Canada," spokesman Richard Walker said, without providing further details.

The arrest of Sarah McIver, a teacher accused of working illegally in China, was announced shortly after that of two other Canadian nationals: former diplomat Michael Kovrig, employed by think tank International Crisis Group, and Michael Spavor, a consultant on North Korea.