A satellite put into orbit by North Korea at the weekend does not appear to be transmitting, but it is worrying that the rocket that took it there delivered twice the payload of Pyongyang's previous launch, the head of the US Army's Missile Defense Command said on Wednesday.
"If you look at the previous launch and the payload it put into orbit … just the increase in weight is I think an important factor," Lieutenant-General David Mann told a seminar on Capitol Hill organised by the Hudson Institute think tank.
"Whenever you are able to put something into orbit, that's significant," Mann said.
"I don't think it's transmitting as we speak, but it does reflect a capability that North Korea is trying to leverage in terms of its missile technologies," he said.
"That kind of capability and then also the collateral usages for that technology are obviously very, very concerning to nations around the world in terms of ICBM (Intercontinental Ballistic Missile) capabilities."
Mann said the payload carried was almost twice as large as that carried in North Korea's previous satellite launch in 2012.
He did not give a figure for the weight of the latest satellite, but South Korean officials have put it at 200-kg (440-lb).
Sunday's launch, which followed Pyongyang's fourth nuclear bomb test on January 6, was condemned by the United States and countries around the world, which believe it was cover for development of ballistic missile technology.
The United States and South Korea immediately said they would begin formal talks about deploying the sophisticated US Terminal High Altitude Area Defense system, or THAAD, to the Korean peninsula "at the earliest possible date."
South Korea had in the past been reluctant to begin formal talks on the Lockheed Martin Corp missile defence system due to worries about upsetting China, its biggest trading partner, which believes it could reduce the effectiveness of its strategic deterrent.
Asked when THAAD might go to South Korea, Mann said there was no timeline for a possible deployment, but added: "I think both governments are going to begin conversations looking at the feasibility of THAAD and we will see what happens from there."
On Wednesday, Russia's Foreign Ministry said US plans for a missile shield in South Korea could trigger an arms race in Northeast Asia.