MOSCOW — Russia said yesterday that U.S. military plans to shoot down a damaged spy satellite may be a veiled test of America's missile defense system.

The Pentagon failed to provide "enough arguments" to back its plan to smash the satellite next week with a missile, Russia's Defense Ministry said in a statement.

"There is an impression that the United States is trying to use the accident with its satellite to test its national anti-missile defense system's capability to destroy other countries' satellites," the ministry said.

The Bush administration says the operation is not a test of a program to kill other nations' orbiting communications and intelligence capabilities. U.S. diplomats around the world have been instructed to inform governments that it is meant to protect people from 1,000 pounds of toxic fuel on the bus-sized satellite hurtling toward Earth.

The diplomats were told to distinguish the upcoming attempt from last year's test by China of a missile specifically designed to take out satellites, which was criticized by the United States and other countries.

Known by its military designation US 193, the satellite was launched in December 2006. It lost power and its central computer failed almost immediately afterward, leaving it uncontrollable. It carried a sophisticated and secret imaging sensor.

Left alone, the satellite would likely hit Earth during the first week of March. About half of the 5,000-pound spacecraft would probably survive its blazing descent through the atmosphere and would scatter debris over several hundred miles.

Military and administration officials said the satellite is carrying fuel called hydrazine that could injure or kill people who are near it when it hits the ground.

The operation to shoot down the dead satellite could happen as soon as this week.