China is investigating a Canadian couple who ran a coffee shop on the Chinese border with the Democratic People's Republic of Korea for the suspected theft of military and intelligence information and for threatening national security, the Foreign Ministry said on Tuesday.

Xinhua News Agency identified the two as Kevin Garratt and Julia Dawn Garratt. In a brief report, Xinhua said the State Security Bureau of Dandong, Liaoning province, was investigating the case, adding that it involved the stealing of State secrets.

Neither the Foreign Ministry nor Xinhua said whether the couple had been detained, although the ministry said the Canadian embassy in Beijing was notified on Monday and that the couple's "various rights have been fully guaranteed".

The Canadian embassy said it was aware of the reports and was gathering information.

"Our consular officials stand ready to provide assistance as required," embassy spokeswoman Mary Anne Dehler said.

Canadian newspaper The Globe & Mail said the Vancouver couple had been living in China since 1984 and opened a coffee shop called Peter's Coffee House in Dandong, a gateway to the DPRK, in 2008. The couple previously worked as teachers in southern China.

"Kevin Garratt and his wife ... are suspected of collecting and stealing intelligence materials related to Chinese military targets and important Chinese national defense scientific research programs, and engaging in activities that endanger China's national security," the Foreign Ministry said in a short statement.

The theft of State secrets is punishable with life in prison or the death penalty in severe cases, according to China's State secrets law.

The Garratts' coffee shop has a view of traffic flowing across the Yalu River that divides China and the DPRK, according to The Globe & Mail. The couple also had a side business helping people plan tours there, it added.

The newspaper said the shop was named after the couple's youngest son. The couple have three children, said David Etter, an American who knew the family and had run a restaurant in another city bordering the DPRK.

He said the Garratts had lived in Dandong for at least six years.

In July, Chinese prosecutors charged British corporate investigator Peter Humphrey and his American wife, Yu Yingzeng, with illegally obtaining private information. They were detained last year following work they did for the British drug maker GlaxoSmithKline Plc. Their trial is set for Aug 8 in Shanghai.