Image copyright SIMEON GARRATT Image caption Julia and Kevin Garratt (centre) with their children Peter and Hannah. Their second son Simeon is not pictured

A Canadian man detained in China since 2014 has been charged with stealing state secrets, say state media.

China's official Xinhua News Agency said Kevin Garratt had been charged in Dandong city, Liaoning province, which borders North Korea.

Xinhua said authorities had found evidence that Mr Garratt accepted tasks from Canadian espionage agencies to gather intelligence in China.

The Canadian government said it was concerned and monitoring developments.

Correspondents describe China's "state secrets" law as notoriously vague, including the definition of what constitutes a state secret.

Mr Garratt and his wife, Julie, were arrested in August 2014. Mrs Garratt was later released.

Their son, Simeon, has said that his parents ran a coffee shop and did Christian aid work for North Koreans.

Image copyright AFP Image caption The couple live in Dandong, at the main China-North Korea border

"The Government of Canada has raised this case with the Chinese Government at high levels .... We remain in contact with Chinese authorities and the family, and are monitoring developments closely," said Canadian foreign ministry spokesperson Francois Lasalle.

Dandong is the main China-North Korea border crossing and trade link. It is a key transit point for North Korean refugees, some of whom are aided by NGOs or Christian groups.