A UN human-rights investigator has strongly criticised North Korea, urging it to end public executions and provide food for the people not just the elite.
In a report, Vitit Muntarbhorn also highlighted the continuing punishment of those who try to leave the country, as well as those forcibly returned.
Mr Muntarbhorn acknowledged some small advances, but said overall the rights situation was "very negative".
He is not allowed into the country, relying instead on testimony.
Mr Muntarbhorn - a Thai expert in human-rights law - was at UN headquarters in New York to present his report to the General Assembly.
He called for an end to public executions and for the North Korean authorities to stop punishing asylum seekers who have been forced to return - such as sending them to labour camps.
Asked about the number of people held in such camps, he said several sources had suggested they housed "very large numbers".
He added that collective punishment was also taking place. "If the dad falls out of favour with authorities, it is the whole family that is carted off to prison," he said.
Mr Muntarbhorn pointed to a number of areas in which the rights situation in North Korea appeared to have deteriorated, such as restrictions on mobile phones and long-distance calls.
He also highlighted reports of a crackdown on North Koreans who watch video and TV programmes from South Korea.
While the ruling elite has enough food, he said, there is a chronic shortage for everyone else, which has only been made worse by floods in 2006 and 2007.
The gap between the haves and the have-nots was on the increase, said Mr Muntarbhorn, who depicted North Korea as a society focused on its military, with an entrenched hierarchy intent upon self-preservation.
Mr Muntarbhorn noted some limited advances, including North Korea's recent invitation to the International Narcotics Control Board to visit the country.
He also welcomed the country's decision to give the UN and aid agencies greater access to those in need.
But he concluded, "the human rights situation in the Democratic People's Republic of Korea [North Korea] remains grave" in key areas.
He also urged the international community to support long-term food security in North Korea.