The Democratic People's Republic of Korea said on Sunday it was considering postponing a launch window for a rocket that the country planned to fire between Monday and Dec 20, while analysts said it's unlikely Pyongyang will cancel the launch unless the international community drops sanctions against it.

"We are now in the final stage of preparations for the launch," the official Korean Central News Agency quoted the Korean Committee for Space Technology as saying, but scientists and engineers were "considering seriously the possibility of readjusting the launch period" because some problems have arisen during the preparation.

A US think-tank, the US-Korea Institute at Johns Hopkins University, said preparations for the launch may have been delayed by heavy snow.

But a senior government source in Seoul said the launch was apparently rescheduled due to "technical problems" and "abnormal signs" that have been spotted since Saturday afternoon, Republic of Korea's Yonhap News Agency said on Sunday.

Experts said neighboring countries should remain alert since it's unlikely the Democratic People's Republic of Korea will pass up the opportunity to draw international attention to the country.

This month will see important elections in Japan and the ROK. The scheduled launch date also comes shortly before US President Barack Obama's inauguration for his second term in January.

Pyongyang aims to influence the ROK presidential candidates' policies on the Korean Peninsula and consolidate the new leadership under Kim Jong-un as the first anniversary of the death of its former leader Kim Jong-il falls on Dec 17, said Wang Junsheng, a researcher of East Asian studies with the Chinese Academy of Social Sciences.

The DPRK is under sanctions and banned under UN Security Council resolutions from conducting any test using "ballistic missile technology". Pyongyang has conducted two nuclear tests, one in 2006 and one in 2009.

The latest plan announced on Dec 1 said it would launch a three-stage rocket mounted with a satellite into orbit, but the United States and its main Asian military allies, the ROK and Japan, insist the launch is a disguised ballistic missile test.

Regional tension has flared up over the past week as various parties have ramped up diplomatic and military pressure urging the DPRK to cancel the launch, the second attempt this year after a failed one in April.

Japanese Prime Minister Yoshihiko Noda on Sunday said Tokyo remained alert, two days after its defense ministry issued an order to shoot down the rocket if it threatens the nation's territory.

Washington sent the anti-missile destroyers USS Benfold and USS Fitzgerald to the area to "monitor any potential missile launch by North Korea and to reassure regional allies should a launch occur", a US Navy official said.

Two ROK destroyers will be deployed in the Yellow Sea in the coming days to track the DPRK rocket, defense officials in Seoul said on Friday.

"Actually, the DPRK's military threats to the region have been exaggerated, while the US and its Asian allies' increasing military presence there has worsened regional stability," said Yu Shaohua, director of the Department for Asia-Pacific Security and Cooperation Studies of the China Institute of International Studies.

The involved parties should consider that multiple years of sanctions have had little effect on Pyongyang, Yu said, adding that those countries may try to achieve a breakthrough with the DPRK using alternative measures after the leadership changes take place.

AFP and Reuters contributed to this story.