Pentagon officials say the Theatre High Altitude Area Defence missile - or Thaad - intercepted and destroyed its target high over New Mexico.

The first successful launch after six failures

Military experts said the flight of the target - a Hera test rocket - simulated that of a Scud ballistic missile such as those fired by Iraq during the 1991 Gulf War.

Thaad's radar, tracking and other integrated system components reportedly worked perfectly.

The successful test followed six costly failures at the military's White Sands missile test range. Nearly $4bn has been spent on development of Thaad since 1992.

Protecting US troops

The new system, being developed by Lockheed Martin Corporation, is aimed at protecting troops in the field by tracking and destroying medium-range enemy missiles well before they plunge to earth.

Republican Representative Curt Weldon, chairman of the House Armed Services Committee, praised the success, saying it demonstrated that Thaad would be effective in protecting US troops overseas from ballistic missile attack.

But the independent Union of Concerned Scientists, which watches military technical issues from Washington, warned that the successful hit under tightly controlled conditions did not prove Thaad could work "against real-world missiles".