An international human rights group is urging North Korean leader Kim Jong-un to halt forcing its people to engage in forced labor without due compensation, a report by a U.S.-based media outlet said Friday.

The report carried by Radio Free Asia (RFA) said the Human Rights Watch sent a letter to Kim calling for an end to mandatory forced labor, and requested that Pyongyang become a member of the International Labor Organization under the United Nations.

The move by the New York-headquartered non-governmental organization (NGO) comes as a large number of North Korean citizens were forced to work ahead of the rare Workers' Party of Korea's congress that kicked off earlier in the day.

North Korea had mobilized ordinary citizens to prepare for the congress under a "70-day campaign of loyalty" and forced them to work longer hours and even donate money to authorities. This has caused a rise in discontent among ordinary people, according to government officials in Seoul.

The loyalty campaign also comes as the North has become ever more isolated after the U.N. slapped it with the toughest ever sanctions after the country detonated its fourth nuclear device in January and followed up on this provocation with the firing of a long-range ballistic missile.

The NGO's letter pointed out that Kim, who assumed power after the death of his father in late 2011, pledged numerous times to improve the livelihood of ordinary people, but so far he has not kept his promise. (Yonhap)