"Japan is reporting that, as far as they can tell, there are no plans to launch a missile today," Snow told CBS' "Face the Nation."

The Taepodong-2 is the North's most advance missile and is capable of reaching parts of the United States with a light payload.

In Tokyo, Japanese Foreign Minister Taro Aso said his country would take the issue to the United Nations.

"We will naturally file a stern protest and it will be fierce," Aso told TV Asahi.

He also said it would be "inevitable" that the Security Council would consider imposing sanctions on North Korea if it goes ahead with a launch. Japan also could impose sanctions on the North, he told Fuji TV.

Snow said he could not discuss specific intelligence about the suspected plans to launch a missile.

But Japan's largest newspaper, Yomiuri, reported Sunday that US and Japanese officials have confirmed that North Korea has assembled what is believed to be a Taepodong-2, with two stages at the launch site, based on photos from satellites.

The newspaper and South Korea's Yonhap news agency carried similar reports citing unidentified US and diplomatic officials saying North Korea also may have begun fueling the missile.

North Korean officials talked Sunday about increasing the country's "military deterrent" during a meeting celebrating the anniversary of leader Kim Jong Il starting work in the communist party, the North's official Korean Central News Agency said.

"Military deterrent" commonly refers to the nuclear program, which North Korea says it needs to defend itself against a potential US attack.

"The (North) Korean army and people will do their best to increase the military deterrent with sharp vigilance to cope with the moves of the US, which is hell-bent on provocations for war," said Choe Thae Bok, secretary of the Central Committee of the Workers' Party of Korea.

"If the enemies ignite a war eventually, the Korean army and people will mercilessly wipe out the aggressors and give vent to the deep-rooted grudge of the nation," Choe was quoted as saying by the North Korean news agency.

The missile concerns come amid an extended impasse at the six-nation talks on the nuclear weapons program. The talks - involving the United States, the two Koreas, China, Japan and Russia - were last held in November.

"We expect them to come back to the table. We do not want to have a missile test out of North Korea," Snow told "Fox News Sunday."

The North claims it has nuclear weapons, but it is not believed to have a design that would be small and light enough to top a missile.