North Korea said Wednesday it had deported an American aid worker accused of using her humanitarian status as a cover to gather and produce anti-Pyongyang propaganda.

Pyongyang's official KCNA news agency identified the worker as Sandra Suh and said she had been a frequent visitor to North Korea in the past 20 years "under the pretense of humanitarianism."

She had "engaged in plot-breeding" and secretly taken photos and produced videos that had then been used as "propaganda abroad," KCNA said.

According to the dispatch, Suh had admitted her crimes and "earnestly begged for pardon".

Although KCNA did not specify how old Suh was, it said the decision to deport rather than detain her had been made "taking into full consideration her old age."

It was unclear exactly when she was deported and the U.S. Embassy in Seoul said it had no immediate comment on the report.

Sandra Suh is registered as having founded a California-based organization, Wheat Mission Ministries, in 1989, to provide food aid and medical technology to North Korea.

The organization's website does not list Suh among its current staff and calls to its office in Los Angeles went unanswered.

Like a number of other humanitarian groups working in North Korea, Wheat Mission Ministries has a Christian grounding.

Pyongyang views foreign missionaries as seditious elements intent on fomenting unrest, but tolerates some faith-based aid groups.