Updated

The world may face a "mad arms race" if the United States goes ahead with its missile defense plans without trying to engage Moscow and assuage its security concerns, the top Russian military officer warned Friday.

Gen. Nikolai Makarov, chief of the military's general staff, urged Washington to reshape its plans so the U.S.-led NATO missile shield in Europe doesn't threaten Russia's nuclear forces.

Makarov said at a meeting with foreign military attaches that failing to do that would force Russia to take countermeasures and trigger a new arms race.

Makarov's statement echoed a similar warning issued repeatedly by President Dmitry Medvedev, who said the world could be thrown back to the Cold War if NATO fails to cooperate with Russia on missile defense.

Russia sees the U.S.-led missile defense plans as a potential threat to its security. It has agreed to consider NATO's proposal last fall to cooperate on the missile shield, but insisted the system be run jointly. NATO rejected that demand and no compromise has been found yet.

"If we fail to agree, Europe will slide back to the early 1980s," Medvedev said at a judicial forum in St. Petersburg. "I don't want to live in such a Europe."

Makarov and other senior Russian military officers who spoke at Friday's conference in Moscow said while Russia isn't concerned about the existing U.S. missile shield, new U.S. missile defense elements will pose a threat to Russian nuclear forces.

They said starting in 2015, the U.S. missile defenses would become increasingly capable of shooting down Russian ballistic missiles.

"Around 2020, one party may get an idea that a nuclear parity no longer matters," Makarov said. "Naturally, Russia will take steps to counter that system."

He said European nations would also have to boost their defense spending to help protect the U.S. missile defense sites they would be hosting.

"In five or six years, a mad arms race could start. And that process could last indefinitely," Makarov said.

The U.S. says the prospective shield aims to fend off Iranian missile threats and isn't aimed against Russia, but Moscow says it wants legal guarantees on that.

Makarov said Russia is open to discuss other possible nuclear defense options, saying perhaps Russia's early warning and information assets could be merged with NATO in one joint system. "They can be controlled from a joint control facility by rotating personnel," he said.

"We are ready to go as far as the alliance is," Makarov added. "If we want to have a predictable and stable peace, we must make all decisions jointly and trust each other."