North Korea appears to be moving ahead with preparations to launch a long-range rocket, despite international condemnation.

South Korean media quoted government officials saying Tuesday that North Korea is preparing the second and third stages of its launch vehicle at the Tongchang-ri facility.

Pyongyang says it plans to launch the three-stage rocket between December 10 and 22. It says the launch is aimed at placing a satellite into orbit.

Its neighbors and much of the rest of the world have warned against the launch, saying it is really a disguised missile test banned under U.N. sanctions.

U.N. Secretary-General Ban Ki-moon said Tuesday he is “seriously concerned” about the launch, saying it would raise tension in the region. Mr. Ban called on Pyongyang to reconsider its decision and halt all activities related to its ballistic missile program.

The United States said any North Korean “satellite” launch would be a highly provocative act that threatens peace and security in the region.

A spokeswoman for the State Department, Victoria Nuland issued a statement saying that devoting scarce resources to the development of nuclear weapons and long-range missiles will only further isolate and impoverish North Korea. She said the path to security for North Korea lies in investing in its people and abiding by its commitments and international obligations.

The United States is consulting closely with its Six-Party and other key allies and partners on next steps.

North Korea's main ally China also added increasing diplomatic pressure, with Foreign Ministry spokesperson Hong Lei warning Pyongyang to “act prudently” and not take steps to escalate the situation.

Seoul's Foreign Ministry spokesperson Cho Tai-young said he hopes China will keep the pressure on North Korea.

“Especially with regard to the Korean peninsula issue, China is a nation that is very closely involved. In that matter we look forward to China playing an active role in maintaining and improving the peace and stability of the Korean peninsula.”

Diplomats from South Korea, Japan and the United States are preparing to meet in Washington this week to discuss the launch, which is scheduled to take place roughly around the one-year anniversary of the death of North Korean leader Kim Jong Il.