South Korea said Thursday, February 4 it has detected preparations by rival North Korea to fire a long-range rocket and warned that Seoul will shoot down any rocket parts flying over South Korean territory, the Associated Press reports.

North Korea told international organizations Tuesday that it will launch an observation satellite aboard a rocket between February 8 and 25. South Korea, the United States and others call the plans a cover for a banned test of a missile that could strike the U.S. mainland.

South Korean defense officials said Thursday that the North is pushing ahead with the launch plans at its Tongchang-ri launch site on its west coast. They refused to provide details because they said they involve confidential intelligence on the North, AP says.

Recent commercial satellite images showed an increased number of vehicles at North Korea's Sohae launch station on February 1, compared to a week earlier. This suggests that the North is preparing for a space launch in coming weeks, according to 38 North, a North Korea-focused website run by the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies.

However, the website said it was impossible to tell from the satellite imagery whether a space launch vehicle was present.

South Korea's president on Thursday called for strong UN sanctions that will make North Korea realize it cannot survive if it does not abandon its weapons programs.

There are questions, however, over whether any sanctions will force real change in the North because China, the North's last major ally and a veto-wielding UN Security Council member, is reluctant to join in any harsh punishment against the North.