WASHINGTON — North Korea may be able to overcome technical difficulties and assemble a missile capable of hitting West Coast cities within three years, a top Defense Department official said Tuesday, but it is unlikely to be able to deliver a nuclear warhead in that time frame.
The U.S. assessment came as North Korea's rulers show signs of preparing for additional weapons tests in the face of international condemnation and new United Nations sanctions.
The estimate of three to five years was provided in congressional testimony by Marine Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff, who previously oversaw America's nuclear forces as head of Strategic Command. It follows North Korea's most recent tests, including a nuclear detonation last month and a multistage missile launch in April that indicated progress but also highlighted flaws in the country's technology.
At the White House, President Obama met Tuesday with South Korea's president, saying he would end the cycle in which the North Korean government provokes international crises to obtain aid.
North Korea in the past has promised to curtail its nuclear program in exchange for energy and economic aid.
"This is a pattern they've come to expect," Obama said. "We are going to break that pattern."
At a news conference with President Lee Myung-bak of South Korea, Obama called North Korea a "grave threat." He emphasized that a chief U.S. concern is that North Korea may spread nuclear technology to other countries or extremist groups. But he also stressed the importance of negotiations.
Cartwright outlined the potential threat posed by North Korean missiles in testimony before the Senate Armed Services Committee. North Korea's Taepodong 2 missile is designed to reach the West Coast of the U.S., but test launches to date have been partial failures.
Analysts believe the Taepodong 2 is inaccurate and so far has failed to reach a third stage, a critical leap to be able to hit the United States.
Cartwright said that in three to five years, the government in Pyongyang might be able to overcome its technical problems.
But he said that time frame did not include development of a warhead.
He did not estimate how long it might take the communist regime to develop a warhead small enough to put on a long-range missile.
Cartwright also stressed that his assessment represented an estimate.
