N. Korea Preparing Long-Range Missile

North Korea is preparing to launch its most advanced missile, believed to be capable of reaching Alaska, from its west coast near China, news reports said Monday.

With the launch, the reclusive communist country could thumb its nose at U.N. Security Council attempts to rein it in after last week's nuclear test and a series of short-range missile launches.

One South Korean report said the launch could be ready by the time South Korean President Lee Myung-bak meets with President Obama on June 16.

South Korean news reports said the North has transported a long-range missile to a newly completed launch pad. And Yonhap news agency said South Korea is studying an intelligence report that the North has ordered troops along the west coast to double their stocks of ammunition.

Yonhap cited an unnamed government official as saying vehicle activity to and from military bases along the coast has increased. South Korea's Defense Ministry declined to confirm the report.

U.S. Defense Secretary Robert Gates, speaking at a news conference in the Philippines, said North Korea appears to be working on a long-range missile but it's not clear yet what they plan to do with it.

Lee, hosting a conference of Southeast Asian leaders on the southern island of Jeju, warned North Korea against any provocation.

"If North Korea turns its back on dialogue and peace and dares to carry out military threats and provocations, the Republic of Korea will never tolerate that," Lee said in his regular radio address. "I want to make clear that there won't be any compromise on things that threaten our nation's security."

The new missile could be ready to launch as soon as mid-June, in time for a summit between Lee and Mr. Obama in Washington on June 16, according to the Dong-a Ilbo newspaper.

Adding to tensions this week, the trial starts Thursday in Pyongyang of two American journalists, Laura Ling and Euna Lee, accused of entering the country illegally and engaging in "hostile acts."

North Korea faced strong international criticism after its last long-range missile launch, on April 5. The North said the launch was of a rocket intended to put a satellite in orbit. That Taepodong-2 rocket flew about 2,000 miles, crossing over Japan before crashing into the Pacific Ocean.

In late April, the North threatened to conduct nuclear and long-range missile tests unless the Security Council apologized for criticizing the launch. On Friday, it threatened to take a further "self-defense" measure if the Security Council provokes it. That threat was seen as referring to an ICBM test.

The United States is currently pushing for a new resolution from the U.N. Security Council that will take a harder line against the recalcitrant communist regime.

Speaking in Singapore during the weekend, Defense Secretary Gates urged America's Asian allies to back tough new sanctions on Pyongyang, including a possible U.N. naval blockade of the country.

The Security Council considered a naval blockade - checking ships entering North Korean ports for contraband - after the last long-range missile test in early April, reports CBS News correspondent Kimberly Dozier. But they never imposed it, fearing it would push Pyongyang into exactly the kind of behavior it's exhibiting now.

The North Korea government has told its people it faces imminent attack, and has threatened everything from the new rocket launch to all-out war if the U.N. blockades Pyongyang, reports Dozier.

In another sign that a new launch is in the works, the North has designated a large area off its west coast as a "no-sail" zone through the end of next month, the Chosun Ilbo newspaper said, citing unidentified intelligence officials.

Experts said the preparations were especially significant because the North has never launched a long-range missile from the northwestern base.

Kim Tae-woo, vice president of Seoul's state-run Korea Institute for Defense Analyses, said he thinks the North chose the site because of its proximity to China, making it more risky for the U.S. to strike.

The site is about 40 miles from the Chinese border city of Dandong.

The missile being prepared for launch is believed to be an intercontinental ballistic missile with a range of up to 4,000 miles, the JoongAng Ilbo reported, citing an unnamed South Korean official.

That would put Alaska within striking range.

On Monday, the North said again that it is being provoked by South Korea and the United States, saying that the number of spy planes operating in its airspace has risen dramatically.

"The U.S. imperialists and the South Korean puppets perpetrated at least 200 cases of aerial espionage against the DPRK in May, or 30 cases more than those in the same month of last year," it said in a report in its official Korean Central News Agency.

The DPRK is an abbreviation of North Korea's official name.

The North's missile and nuclear programs have been considered a top regional security concern, though the regime is not yet believed to have mastered the technology to make a nuclear warhead small enough to mount on a missile.