The United States will conduct its next test of an antiballistic missile it has jointly developed with Japan by the end of the year, following a test failure in January, a Pentagon official said Wednesday.

The Standard Missile-3 Block IIA is "an extremely capable interceptor," said Lt. Gen. Samuel Greaves, director of the Missile Defense Agency under the Defense Department, at a Senate hearing.

The agency believes a "specific component" did not function as designed in the January test, but the missile has flown successfully "nine out of 10 times," Greaves said.

"As of now, I am not concerned that it is a true design issue," he told the defense subcommittee of the Senate Appropriations Committee. "And we're following through to identify the problem and then correct it."

"The next test will be before the end of this calendar year," he said.

On Jan. 31, an SM-3 Block IIA was launched from Hawaii using Aegis Ashore technology, a land-based variant of the Aegis ballistic missile defense system, but failed to intercept an incoming dummy missile.

The SM-3 Block IIA can be employed on Aegis-equipped destroyers as well as with the Aegis Ashore system that Japan decided last December to deploy.

In early January, the United States approved a plan to sell four SM-3 Block IIA missiles to Japan.