Updated

North Korea said Thursday it has detained an American man for illegally entering the country from China, the second arrest of a U.S. citizen it has reported in the past several weeks.

The man was detained Monday and is under investigation, the North's official Korean Central News Agency said in a brief dispatch. It did not identify him by name or provide other details.

In Washington, State Department officials did not immediately respond to requests for comment. The U.S. embassies in Beijing and Seoul said they had no comment.

North Korea said late last month that it was holding another U.S. citizen for illegally entering through the North Korea-China border.

It did not identify the man, but he is widely believed to be Robert Park, an American missionary who South Korean activists say crossed over a frozen river into North Korea several days earlier to raise the issue of human rights.

U.S. officials are still seeking consular access to that citizen, U.S. State Department spokesman P.J. Crowley told reporters Wednesday. The U.S. hopes to gain access to him through the Swedish Embassy in Pyongyang since Washington does not have diplomatic ties with North Korea. The two countries are technically in a state of war since the 1950-53 Korean War ended with an armistice, not a peace treaty.

A South Korean activist who has been the source of most information about the missionary said Thursday that he has no knowledge of the second American detainee.

Jo Sung-rae of the Seoul-based group Pax Koreana said he and fellow activists sent about 150,000 leaflets by balloon across the border into North Korea on Wednesday as part of efforts to let North Koreans know about Park.

Jo said the leaflets repeated Park's demand that North Korean leader Kim Jong Il step down and dismantle camps for political prisoners.

Park's detainment came four months after two American journalists arrested at the border were freed and their 12-year sentences for illegal entry and "hostile acts" were commuted after former President Bill Clinton traveled to Pyongyang and met North Korean leader Kim.