"We are consulting closely in capitals and at the United Nations in New York and we will be pursuing appropriate action," Clinton said at a press conference with Japanese Foreign Minister Koichiro Gemba, who echoed her remarks.

"If North Korea wants a peaceful, better future for their people, it should not conduct another launch that would be a direct threat to regional security," the chief US diplomat said.

Gemba spoke of US-Japanese cooperation if North Korea goes ahead with the launch of a rocket it says will put a satellite into orbit -- an event that most of the rest of the world sees as a disguised missile test.

"The United States and Japan would cooperate with each other and the international community, including the Security Council, would take an appropriate measure," Gemba said.

Neither Clinton nor Gemba explained what they meant by "appropriate" action.

Both top diplomats reiterated that the launch would violate UN Security Council resolutions 1718 and 1874, which ban ballistic missile activity.

On April 5, 2009, North Korea launched a long-range rocket which flew over Japan and landed in the Pacific in what it says was an attempt to put a satellite into orbit.

US State Department spokeswoman Victoria Nuland earlier voiced concern that the international news media might be "playing" into North Korean propaganda by covering the rocket launch.

"Our concern obviously would be that the North Koreans would use this for propaganda purposes and that... news organizations that cover it extensively might be playing into that," Nuland said.

"But it's obviously your call how to cover this thing," she told reporters during the daily news briefing.

The usually secretive North organized an unprecedented visit for foreign reporters to Tongchang-ri space center in an effort to show its Unha-3 rocket is not a disguised ballistic missile, as claimed by the US and its allies.

The launch is scheduled between April 12 and 16 to mark the 100th anniversary of the birth of North Korea's founding leader Kim Il-Sung, a significant date as Kim's youthful grandson Kim Jong-Un cements his own power.

With world attention focused on North Korea's expected imminent launch of a long-range rocket, a US official said that pressing the ultra-authoritarian state over its dire human rights record was also "integral" to US policy.

Pyongyang "must respect human rights in order for the North to participate fully in the international community and we continue to make that point to the North Koreans at every opportunity that we have," said Robert King, the US special envoy on human rights in North Korea.

King said that the media was partially to blame for the lack of attention as "they tend to have greater interest in missiles, rockets and bombs than they do in human rights and prison camps, which are harder to see."

"The North Koreans will allow them to come in and observe the launch of a missile. They won't let them watch what goes on in a prison camp," King said.

North Korea has invited international journalists to see preparations for what it describes as a satellite launch as part of nationwide celebrations to mark the 100th anniversary of the birth of the regime's founder Kim Il-Sung.

King was addressing the Committee for Human Rights in North Korea, a Washington-based advocacy group that released a 200-page report urging the dismantling of what it called a vast system of political prison camps.

The study, in line with previous reports, estimated that 150,000 to 200,000 political prisoners are locked up in North Korea -- some for offenses as small as singing songs from democratic South Korea or visiting neighboring China.

Based on interviews with 60 former prisoners or guards, the study found "exorbitant rates of deaths in detention" as a result of "systemic and severe mistreatment, torture, executions and induced malnutrition."

The report, led by human rights specialist David Hawk, renewed charges that North Korea locks up entire families for political crimes of relatives and forces women into abortion if they become pregnant from Chinese men after slipping across the border.

The study urged access by the International Committee for the Red Cross and the World Food Program to prison camps, which North Korea says do not exist.

King was non-committal on calls for a United Nations investigation into prison camps. He said that no US decision has been taken but that such a move may impede work of a UN special rapporteur on human rights in North Korea.

In a petition last week, activists calling themselves the International Coalition to Stop Crimes against Humanity in North Korea urged a UN probe and estimated that 400,000 inmates have died in the past few decades from starvation or overwork.

In one of the most dramatic accounts of the prisons, a new book by former Washington Post journalist Blaine Harden entitled "Escape from Camp 14" tells the story of Shin Dong-Hyuk, described as the only North Korean to escape a camp.

Shin, who spent more than 22 years in the camp before fleeing to South Korea and eventually the United States, told the forum that he was reminded of his experience during visits to the US Holocaust Memorial Museum in Washington.

"We think the Holocaust is a thing of the past, but it is not. This continues in North Korea," Shin said, recalling that he and fellow prisoners were regularly forced to watch public executions.

"If something were to happen to the North Korean regime, there will be collective execution" of all prisoners, he said. "North Korea is capable of doing this."