AFP - A US citizen facing trial in communist North Korea for illegal entry is a deeply religious man who previously taught English in South Korea, former colleagues said Tuesday.

Disclosing his identity for the first time since his arrest on January 25, the North said Monday that Aijalon Mahli Gomes, 30, of Boston, would be indicted for trial "as his crime has been confirmed."

The one-paragraph report gave no other details. The North had announced on January 28 the detention of an American whom it did not identify for illegal entry.

Gomes' motives remain unclear.

Authorities at Sinbong Elementary School in Pocheon City, north of Seoul, said he taught English there from April 2008 to March last year.

"All the memories we have about Gomes, who is an African-American, are only good. Everyone here liked him," school headmaster Cho Kyoo-Sig told AFP.

"I remember him as a very mellow and calm person. He was very kind to everybody and all the children liked him so much.

Gomes left the school, saying he would find a better-paying job in Uijeongbu City next to Seoul.

"If he wants to return to this school, he would always be welcome. It's hard to find a native English teacher as good as Gomes," Cho said.

A teacher said Gomes was a "deeply religious person."

"He acted like an evangelist. He took the trouble to commute to Seoul to participate in Wednesday prayer sessions at a foreigners' church there," she said.

"He was also engaged in community service, working as a volunteer at a day care centre."

The US State Department did not confirm the man's identity, but lamented the lack of transparency surrounding the case.

It said it would continue to monitor the situation through the Swedish embassy in Pyongyang to ensure he has appropriate representation in any legal proceedings.

Analysts have said that despite the trial announcement, the communist state may be preparing to expel Gomes as a goodwill gesture.

Pyongyang is pressing Washington to agree to hold talks about a permanent peace pact to replace the armistice which ended the 1950-53 Korean War.

It wants the US commitment to discuss a peace pact, and a lifting of United Nations sanctions, before it returns to six-nation nuclear disarmament talks.

In a separate case, US missionary Robert Park walked into North Korea on Christmas Day carrying a letter calling on leader Kim Jong-Il to quit because of rights abuses.

North Korea freed Park in February. Its official news agency quoted him as saying he had been misled by false Western propaganda about rights abuses and a lack of religious freedom in the North.

In March last year the communist state detained two female US television journalists for illegal entry.

It sentenced them to 12 years of hard labour but pardoned them when former US president Bill Clinton flew to Pyongyang last August and met Kim Jong-Il.

Pyongyang announced in late February it was investigating four South Koreans detained for illegal entry, but has since said nothing about the case.

The Seoul government has said it is trying to identify them. A South Korean activist said at the time the four, who may have been evangelists, had crossed from China in an attempt to meet leader Kim.