SEOUL, South Korea -- North Korea prepared to test-fire missiles at launch pads on both of its coasts, reports and experts said Tuesday, as South Korea beefed up its naval defenses.
The moves heightened tensions in the region following North Korea's underground nuclear test last week.
North Korea may soon launch three or four midrange missiles, thought to be modified versions of its Rodong series, from its east coast, South Korea's Yonhap News Agency reported. An American military official confirmed an intercontinental ballistic missile capable of striking Alaska was being readied at a base on the North's west coast.
The U.N. Security Council is considering measures to punish the North for the nuclear test, and U.S. deputy secretary of state James Steinberg said Tuesday that Washington is looking for "creative ideas."
"There are a number of very creative ideas that we are sharing with partners," he said after a talk with Japanese Prime Minister Taro Aso in Tokyo.
Pyongyang has countered that it will not accept any punishment and has warned it won't respect the 1953 truce that ended the Korean War if it is provoked.
Fearing skirmishes off its coast, South Korea, whose troops are already on high alert, sent a high-speed ship equipped with guided missiles to its western waters, where the North was reportedly staging amphibious assault training.
The ship is ready to "frustrate North Korea's naval provocation intentions and destroy the enemy at the scene in case of provocations," the navy said in a statement.
The long-range missile being prepared by the North is thought to have a range of up to 4,000 miles, the Joong-Ang Ilbo newspaper reported, citing an unnamed South Korean official. That would put Alaska and the Pacific island of Guam, which has major U.S. military assets, within range.
Satellite images indicated the North had transported the missile to the new Dongchang-ni facility near China, Yonhap reported.
A U.S. official confirmed the Yonhap report and said the missile was moved by train, although he did not comment on where it was moved to, and said it could be more than a week before Pyongyang was ready to launch. He spoke on condition of anonymity because it was an intelligence-related issue.
It was not clear when the U.N. Security Council would agree to a new resolution.
The United States and Japan, which is concerned because it is within striking range of North Korean missiles, have pushed hardest for tough new measures, but China and Russia -- traditionally closer to the North -- have been more restrained.
Russia's U.N. envoy said a strong response to North Korea is needed but warned that new sanctions must not further isolate it, according to an interview published Tuesday.
Ambassador Vitaly Churkin told a government daily, the Rossiyskaya Gazeta, that a new resolution should help encourage Pyongyang to return to the six-nation talks aimed at disarming the North.
Complicating the situation for Washington is Thursday's trial in Pyongyang of two American journalists, Laura Ling and Euna Lee, accused of entering the country illegally and engaging in "hostile acts."
North Korea also has custody of a South Korean worker detained at a joint industrial complex at the border. He has been transferred to Pyongyang, Yonhap said Tuesday. It said North Korea has refused to allow the delivery of daily necessities to him.
Associated Press writer Shino Yuasa in Tokyo contributed to this report.