WASHINGTON (Yonhap News) – The United States has the capability to intercept ballistic missiles from North Korea, a senior U.S. official has said.

Patrick O'Reilly, director of the Missile Defense Agency, made the remarks at a House Armed Services Committee hearing Thursday in response to a lawmaker who expressed "concerns about the ground-based midcourse defense system in Alaska and California," citing "back-to-back flight test failures this past year."

"We have two versions of the GMD missile. The first version is called capability enhancement No. 1 and it's the kill vehicle that has performed five times on flight, has done very well, three intercept attempts and it's intercepted three times," O'Reilly said, according to a transcript released by the Pentagon Friday.

Critics are skeptical of the effectiveness of the costly global missile defense systems, citing technological shortfalls and political ramifications, although Defense Secretary Robert Gates and other senior U.S. officials have expressed confidence in the U.S. capability to shoot down any ballistic missiles coming from North Korea.

"Those are flights out of – the target out of Kodiak, Alaska, and the intercept out of Vandenberg (California)," O'Reilly said.

"That roughly equates to the geometry of a launch out of North Korea and an intercept coming out of Fort Greely, Alaska. So for those type of scenarios and for that system, the CE-1, we remain to have confidence in the system based on the data we've seen."

The U.S. also "started a second version of the missile kill vehicle in 2005 based on obsolescence reasons; parts, manufacturers and so forth not producing parts anymore that – and the electronic systems that we needed," he said.

"We redesigned the system, upgraded it, and actually gave a greater sensitivity and greater capability. However, it failed on the first flight test due to a quality control problem. We corrected that quality control problem and in the second flight it didn't happen."

Due to budget constraints, the Obama administration in 2009 cut back a plan that would have increased the number of interceptors to 44 from 30, but administration officials insist 30 interceptors are enough to counter North Korea's missile capability "for some years to come."

Speaking at the hearing, Bradley Roberts, deputy assistant secretary of defense for nuclear and missile defense policy, said that the U.S. has been improving the GMD system against "the threats that might emerge from states like North Korea and Iran to conduct limited strikes on the United States."

Gates said in January that North Korea's missiles and nuclear weapons will pose a threat to the U.S. within five years. Some experts say Pyongyang may have already developed nuclear warheads small enough for missile payloads.

Nuclear-armed North Korea has made a series of provocations in recent months, including the sinking of a South Korean warship and shelling of a border island that killed 50 people last year.

In November, Pyongyang also disclosed a uranium enrichment plant that could be used to make nuclear weapons apart from its plutonium program. The North claims its intention is to generate electricity.