Japan strongly protested North Korea's planned rocket launch, warning Friday it could shoot it down after the North said it would fly over Japan and designated a "danger" zone off the country's coast.

North Korea has given U.N. agencies coordinates forming two zones where parts of the multiple-stage rocket would fall, unveiling its plan to fire the projectile over Japan toward the Pacific Ocean sometime between April 4 and 8.

One of the "danger" zones where the rocket's first stage is expected to fall is in waters less than 75 miles (120 kilometers) from Japan's northwestern shore, according to coordinates released Thursday by the International Civil Aviation Organization and the International Maritime Organization.

The other zone lies in the middle of the Pacific between Japan and Hawaii.

In Tokyo, Chief Cabinet Secretary Takeo Kawamura told North Korea to abandon the launch and said Japan was ready to defend itself.

"Legally speaking, if this object falls toward Japan, we can shoot it down for safety reasons," he said.

Defense Minister Yasukazu Hamada said Japan would "deal with anything that is flying toward us. We are preparing for any kind of emergency."

Japan's prime minister expressed anger.

"They can call it a satellite or whatever, but it would be a violation" of a 2006 U.N. Security Council resolution banning Pyongyang from ballistic missile activity, Taro Aso said. "We protest a launch and strongly demand it be canceled."

Japan's coast guard and Transport Ministry issued maritime and aviation warnings, urging ships and aircraft to stay away from the affected regions.

Hisanori Iizuka, a spokesman for Japan Airlines Corp., Asia's biggest carrier, said the airline will reroute some flights during the April 4-8 period.

"We will take every measure to ensure safety for our passengers," Iizuka said.

South Korea also warned the North.

"If North Korea carries out the launch, we believe there will be discussions and countermeasures from the Security Council," a Foreign Ministry statement said, referring to possible sanctions.

U.N. Secretary-General Ban Ki-moon said Thursday a North Korean satellite or missile launch would "threaten the peace and stability in the region."

Though it is an international norm for countries to provide such specifics as a safety warning ahead of a missile or satellite launch, it was the first time the communist North has done so. It did not issue a warning ahead of its purported satellite launch in 1998 over Japan and a failed 2006 test-flight of a long-range missile.

The North's notification to the ICAO and IMO underscores that it is intent on pushing ahead with the launch in an attempt to gain greater leverage in negotiations with the United States, analysts say.

"They want to do the launch openly while minimizing what the international community may find fault with," said Kim Yong-hyun, a professor at Seoul's Dongguk University. "The launch will earn North Korea a key political asset that would enlarge its negotiating leverage."

U.S. State Department spokesman Robert Wood called the North's plan "provocative."

"We think the North needs to desist, or not carry out this type of provocative act, and sit down ... and work on the process of denuclearization of the Korean peninsula," Wood said.

Analysts, including Kim, say a rocket launch would raise the stakes as well as the benefits the impoverished nation might get from negotiations with the U.S. and other countries trying to persuade it to give up its nuclear weapons program. The North has repeatedly used brinksmanship in the past as a negotiating tool to gain concessions and aid.

Separately, North Korea on Friday barred overland border crossings for the second time this week, leaving hundreds of South Koreans working at a joint industrial complex in the North stranded on both sides of the border.

About 250 people, who are mostly South Koreans but also include an Australian and two Chinese, had planned to return Friday to the South from the complex in the North Korean border town of Kaesong, South Korea's Unification Ministry said, adding that some 610 people were unable to cross the border to the complex.

"Our government expresses our deep regret over the fact that this kind of situation has been repeated," Unification Ministry spokesman Kim Ho-nyeon told reporters.

Kim called the border closing an act "tarnishing" trust between the two Koreas and creating "an obstacle" against the complex's expansion.

It was unclear why the North refused permission for the border crossings. The North closed the border on Monday after cutting off the only remaining hot line with the South to protest its ongoing military drills with the U.S. The North calls the exercises a rehearsal for an invasion.