North Korea has confirmed that it has arrested a US citizen, and is preparing to charge him with "committing a crime" against the country.

朝鲜政府证实已经逮捕一位美国公民，并将以其在朝鲜“犯下罪行”的罪名起诉他。

Jun Young Su was arrested in November last year, the official KCNA news agency said.

The US state department announced the arrest on Tuesday and is calling for the detainee's release on humanitarian¹ grounds.

The US has not named him, but said that Swedish diplomats² had visited him.

The Swedish embassy in Pyongyang looks after American interests, as there are no diplomatic relations between North Korea and the US.

Later this month, former US President Jimmy Carter will fly to Pyongyang on a private visit to discuss issues including nuclear weapons, and would be likely to raise this case as well.

There is a long history of American citizens being held after trespassing³（侵入，犯罪） in North Korea.

Since 2009, it has taken visits to Pyongyang by two former US presidents to secure the release of Americans in detention⁴ there.

This week, US Secretary of State Hillary Clinton is due on a scheduled visit to South Korea.

Efforts to ease tensions on the Korean peninsula are continuing, after two military attacks last year.