Updated

Japan may move Patriot missiles to its northern coast for self-protection in case North Korea's planned rocket launch fails, the defense minister said Tuesday as the prime minister warned of more possible sanctions against Pyongyang.

Defense Minister Yasukazu Hamada said some of the six batteries of PAC-3 missiles, now in and around Tokyo, may be shifted to intercept fragments that might fall into Japanese territory if North Korea's rocket launch, scheduled for sometime between April 4 and 8, goes bad.

"We are considering various measures, including that," Hamada told reporters.

Pyongyang has designated the waters off Akita and Iwate prefectures (states) as a risk zone for falling debris.

Japan's military is also considering mobilizing a pair of destroyers carrying the SM-3 ship-to-air missile defense system from their southern home port of Sasebo, and is in close contact with the U.S. military to coordinate response in case of an emergency, a ministry official said on condition of anonymity, citing department policy.

Earlier Thursday, Prime Minister Taro Aso said Japan could impose more sanctions on North Korea if it goes ahead with the planned rocket launch, regardless of its payload. He said Tokyo also plans to raise the issue with the U.N. Security Council.

"We will make a comprehensive decision, including the possibility of imposing tougher sanctions," Aso told a parliamentary committee.

North Korea says it intends to launch a telecommunications satellite into orbit, but many fear it may be testing ballistic missile technology and have demanded the launch not take place. The North is barred by U.N. sanctions from testing ballistic missiles.

Foreign Minister Hirofumi Nakasone said Japan considers any launch, even if the payload is a satellite, as a missile test. North Korea has indicated that the rocket would be launched in an easterly direction, taking it over Japan and the Pacific Ocean.

"Obviously, it is our country that faces the most serious threat," Nakasone said. "We plan to take a leadership role so that the entire international community will join in solid action to support sanctions."

Members of the ruling party's committee on North Korea are calling for sanctions that include an extension of ongoing economic restrictions from six months to one year, a total export ban and tougher restrictions on money transfers to the North.

Japan imposed tight trade sanctions against Pyongyang in 2006 after it tested ballistic missiles in waters between the two countries and conducted an atomic test. Japan's current sanctions, which have been extended every six months since, are set to expire April 13.

Chief Cabinet Secretary Takeo Kawamura said if the launch fails, rocket fragments could drop on Japan. He also reiterated Tokyo's threat to shoot down any objects that might harm lives or property.

"We must protect the people's lives and assets and we're preparing for any development," he said.