North Korea may postpone the controversial launch of a long-range rocket that had been slated for liftoff as early as this week, state media said Sunday, as international pressure on Pyongyang to cancel the provocative move intensified.

Scientists have been pushing forward with final preparations for the launch from a west coast site, slated to take place as early as Monday, but are considering "readjusting" the timing, an unidentified spokesman for the Korean Committee for Space Technology told North Korea's state-run Korean Central News Agency.

It was unclear whether diplomatic intervention or technical glitches were behind the delay. A brief KCNA dispatch said scientists and technicians were discussing whether to set new launch dates but did not elaborate.

Word of a possible delay comes just days after satellite photos indicated that snow may have slowed launch preparations, and as officials in Washington, Seoul, Tokyo, Moscow and elsewhere urged North Korea to cancel a liftoff widely seen as a violation of bans against missile activity.

Commercial satellite imagery taken by GeoEye on Dec. 4 and shared Friday with the Associated Press by the 38 North and North Korea Tech websites showed the Sohae site northwest of Pyongyang covered with snow. The road from the main assembly building to the launch pad showed no fresh tracks, indicating that the snowfall may have stalled the preparations.

However, analysts believed rocket preparations would have been completed on time for liftoff as early as Monday.

U.S. 'deeply concerned'

North Korea announced earlier this month that it would launch a three-stage rocket mounted with a satellite from its Sohae station southeast of Sinuiju sometime between Dec. 10 and Dec. 22. Pyongyang calls it a peaceful bid to send an observational satellite into space, its second attempt this year.

The launch announcement captured global headlines because of its timing: South Korea and Japan hold key elections this month, U.S. President Barack Obama begins his second term next month and China has just formed a new leadership. North Koreans also have begun a mourning period for late leader Kim Jong Il, who died on Dec. 17, 2011.

Last week, U.S. Secretary of State Hillary Rodham Clinton said Washington was "deeply concerned" about the launch, and urged foreign ministers from NATO and Russia to demand that Pyongyang cancel its plans.

The U.S. and others said the launch would violate UN Security Council resolutions banning North Korea from nuclear and missile activity because the rocket shares the same technology used for firing a long-range missile.

North Korea has unveiled missiles designed to target U.S. soil and has tested two atomic bombs in recent years, but has not shown yet that it has mastered the technology for mounting a nuclear warhead to a long-range missile. Six-nation negotiations to offer North Korea much-needed aid in exchange for nuclear disarmament have been stalled since 2009.

China, the North's main ally and aid provider, noted its "concern" after North Korea declared its plans. It acknowledged North Korea's right to develop its space program but said that had to be harmonized with restrictions including those set by the UN Security Council.

Reasons for delay unclear

In Seoul, officials at the Defence Ministry, Joint Chiefs of Staff and the Foreign Ministry said Sunday they couldn't immediately find what might be behind the possible delay.

North Korea may hold off if Washington actively engages Pyongyang in dialogue and promises to ship stalled food assistance to the country, said Koh Yu-hwan, a professor of North Korean studies at Seoul's Dongguk University.

In February, the U.S. agreed to provide 240,000 metric tons of food aid to North Korea in exchange for a freeze in nuclear and missile activities. The deal collapsed after North Korea attempted to launch a long-range rocket in April. That rocket broke up seconds after liftoff.

Analyst Baek Seung-joo of the South Korean state-run Korea Institute for Defence Analyses in Seoul said China must have sent a "very strong" message calling for the North to cancel the launch plans.

"North Korea won't say it would delay the launch due to foreign pressure so that's why they say scientists and technicians are considering delaying it," he said.