North Korea released video footage on Monday of a Canadian pastor confessing before a Pyongyang church congregation that he had committed crimes against the state.

Hyeon Soo Lim, of the 3,000-member Light Korean Presbyterian Church in Toronto, traveled to North Korea in January this year on a routine humanitarian visit. He has been detained since February.

Dressed in a dark blue suit and tie and speaking to a sparse congregation which included some foreign residents of Pyongyang, South Korean-born Lim appeared to be reading from a script.

"The worst crime I committed was to rashly defame and insult the highest dignity and the system of the republic," Hyeon told a congregation at Pyongyang's Pongsu Church, according to video released by the semi-official Uriminzokkiri propaganda website.

Pongsu Church is one of four state-operated churches in the capital of a country that espouses freedom of religion but effectively bans it.

The service took place on August 2, Uriminzokkiri said.

Last week, the 60-year-old appeared before media in Pyongyang where he also confessed to crimes aimed at overthrowing the state, the North's official news agency said.

KCNA quoted Lim as telling a news conference he had travelled to North Korea in the guise of humanitarian work and gathered information that he used in sermons outside the country in a bid to drive the regime to a collapse "with the love of God."

His purpose was to "overturn its social system by taking advantage of the hostile policy against it sought by the South Korean authorities and set up a base for building a religious state," KCNA quoted him as saying.

Lim has visited North Korea more than 100 times since 1997 and has helped establish an orphanage and a nursing home there, according to the church. He has lived in Canada since 1986 and is a Canadian citizen.

Canada suspended diplomatic relations with Pyongyang in 2010. Both North Korea and neighboring China have clamped down on Christian groups over the past year, and several American Christians have been detained by North Korea.

North and South Korea are still technically at war after their 1950-53 conflict ended in a truce, not a treaty. The reclusive North, which regularly threatens to destroy the United States in a sea of flames, has also been slapped with heavy Western sanctions over its nuclear and missile programs.