SEOUL, South Korea — South Korean technicians scrutinizing the debris of the North Korean rocket launched this month have found evidence suggesting the rocket’s military purposes and the North’s technological ties with Iran in its efforts to develop an intercontinental ballistic missile, South Korean officials said Sunday.

North Korea insists that its Unha-3 rocket, launched Dec. 12 to put an earth-observation satellite in orbit, was part of its peaceful space program. But intelligence officials and rocket scientists affiliated with the South Korean Defense Ministry said Sunday that through the rocket launching, North Korea was testing a ballistic missile that could fly more than 6,200 miles, with a warhead of about 1,100 to 1,300 pounds, putting the West Coast of the United States in range.

They spoke to the news media after analyzing the rocket’s flight data and the debris of its oxidizer tank, which was recovered in waters off South Korea two days after the rocket launching.

Over the weekend, the South Korean Navy also salvaged the remnants of the rocket’s fuel tank and part of its engine, which the officials hoped would provide more clues to the North’s rocket technology.