MOSCOW — Russia will develop missiles impervious to any defense, Defense Minister Sergei Ivanov said yesterday in an apparent allusion the U.S. missile-defense system now under development.

A year ago, President Vladimir Putin said Russia could build unrivaled new strategic weapons, and in November he said it is developing a new nuclear-missile system unlike any weapon other countries have or could come up with in the near future.

Ivanov suggested that the weapons would be based on the mobile version of the Russian Topol-M intercontinental ballistic missiles and on a new sea-based system, the Bulava, according to Interfax news agency.

"There is not and will not be any defense against these missiles," he said, according to Interfax.

The Topol-M can hit targets more than 6,000 miles away, and has been in silos since 1998, with about 40 on duty now, according to military officials. Military officials have said they plan to begin deploying the mobile version this year.

Ivanov said the missiles would be for defense and not be intended for use against any country, but he added that "Russia is stretched across 10 times zones, we have many neighbors, and not all of them are as predictable as European states," according to Interfax.

"Russia will ... remain a major nuclear power," Ivanov said, according to Interfax. "But we will not bake missiles like pies. Their quantity should be such that it allows for the provision of our own security in any potential development of the international situation."

Russia opposed the U.S. withdrawal in 2002 from the 1972 Anti-Ballistic Missile Treaty in order to deploy a national missile-defense shield, saying the 30-year-old U.S.-Soviet pact was a key element of international security.

The ABM treaty banned missile-defense systems on the assumption that the fear of retaliation would prevent each nation from launching a first strike — a strategy known as mutually assured destruction.

The Bush administration has said its prospective missile-defense system would be aimed against potential missile threats from nations such as Iran or North Korea, and would be unable to fend off a massive nuclear strike Russia is capable of launching.