The U.S. government on Tuesday called for North Korea to release an American citizen reportedly detained there several months ago.

State Department spokesman Mark Toner said that Swedish officials had visited the American as the U.S. does not have diplomatic relations with Pyongyang.

Toner gave no details about the arrest, when it happened or the identity of the individual, saying the person had not signed a privacy waiver.

He urged North Korea to treat the citizen "in a manner consistent with international human rights law."

Sweden's Foreign Ministry spokesman Teo Zetterman confirmed that its diplomats were representing the U.S. in the case.

Several Americans have been arrested in North Korea in recent years.

In August, former President Jimmy Carter brought home Aijalon Gomes who was sentenced to eight years' hard labor for crossing into the North from China. He had been detained for seven months.

In 2009, journalists Laura Ling and Euna Lee were arrested for trespassing in North Korea and released only after former President Bill Clinton made a similar trip to Pyongyang to plead for their freedom.