WASHINGTON, June 6 (RIA Novosti) - The United States is planning to conduct three test launches of ballistic missile interceptors by the end of September as part of its missile defense program, a spokesman for Missile Defense Agency (MDA) said.

MDA spokesman Rick Lehner said in an interview with RIA Novosti Tuesday that the agency planned to test a sea-based missile interceptor in late-June or mid-July, a THAAD (short- to mid-range) missile interceptor in July, and a ground-based long-range interceptor in late August-September.

A recent test of a long-range interceptor was aborted May 25 when a target rocket launched from Alaska fell into the Pacific Ocean before an interceptor missile could be launched from California.

"The target did not reach sufficient altitude to be deemed a threat, and so the Ballistic Missile Defense System did not engage it, as designed," Air Force Lt. Gen. Henry Obering III, director of the Missile Defense Agency, said in a statement following the test failure.

Lehner said Tuesday that the failed test would be repeated by using a new "dummy target" or a target missile that had been scheduled for use in a test next fall.

The U.S. has conducted 27 successful tests of its missile defense system since 2001, while seven tests resulted in failure.

The U.S. national missile defense system currently deploys missile interceptors at Fort Greeley, Alaska, and at Vandenberg, about 130 miles (209 kilometers) northwest of Los Angeles.

The United States is also planning to expand its missile shield to sites in the Czech Republic and Poland.

The Kremlin has responded angrily to U.S. plans, announced in January, saying U.S. missile bases in Europe could become targets of its pinpoint strikes.

Russia last week tested a new ballistic missile capable of carrying multiple nuclear warheads and a new cruise missile, saying the tests were part of Moscow's response to U.S. anti-missile plans.