SEOUL (Reuters) – Missiles test-fired by North Korea this week are “a quantum leap forward” from its previous weapons with greater reliability and precision, the commander of the U.S. military in South Korea said.

Speaking before the U.S. House Armed Services Committee on Thursday in Washington, General B.B. Bell said North Korea was also moving ahead with the development of longer-range ballistic missiles that could hit Alaska and targets in the continental United States.

North Korea’s testing of two short-range missiles on Wednesday came during a stalemate in six-country talks aimed at ending its nuclear weapons programs.

Pyongyang says it has nuclear weapons but proliferation experts have questioned its ability to mount them on missiles.

“(They) are, in fact, a quantum leap forward from the kind of missiles that they have produced in the past,” Bell told the hearing, referring to the short-range missiles tested this week.

The missiles were boosted by solid fuel, rather than liquid fuel, providing greater reliability, mobility and precision, he said.

“They are routinely testing these,” Bell told the hearing, according to an audio recording made available on Friday on the U.S. House committee’s Web site.

North Korea test-fired a similar missile in May last year. A senior Bush administration official said the missiles tested this week did not leave North Korean territory.

South Korean daily JoongAng Ilbo said North Korea fired the two missiles from its east coast and they probably dropped into the sea about 100 km (60 miles) away, citing a government source.

Initial reports said the tests were over a shorter distance elsewhere and just on land.

U.S. officials said the missile test proved the North’s nuclear programs posed a threat to the region, but neighbors China and South Korea were muted in their reactions.

This week’s test was more about checking performance than rattling sabers as regional powers work to resume the stalled nuclear talks, analysts said.

Bell said the North was developing longer-range missiles with ranges “far beyond any requirement that they have for defense”.

Pyongyang is ready and willing to sell the technology, posing a great concern about proliferation, Bell said.

“North Korea is a significant threat that still must be deterred,” Bell told the committee.

South and North Korea remain technically at war because the 1950-53 Korean War ended in a truce and not a peace treaty.