Despite the United States’ rejection of the Russian offer, Moscow went ahead Wednesday with its show-and-tell for a wider audience.

Sergei Ryabkov, the deputy foreign minister who deals with arms control, said at the event that the United States had yet to present any data to prove its contention that the missile violates the treaty. He also accused the United States of going through the motions of talks rather than trying to save the treaty.

“The treaty must be preserved,” Mr. Ryabkov said at the briefing, which was broadcast live on national television.

After he spoke, the military rolled one missile and its mobile launcher into a cavernous, otherwise empty convention center. A soldier wearing combat fatigues and a helmet used a green laser pointer to indicate various parts of the missile as General Matveyevskiy described them.

Although there have been some modifications from the previous version of the missile, the 9M728, he stressed that the booster, cruising engine and fuel tank are identical. The older version can fly up to 490 kilometers, he said, and the range of the new one is actually 10 kilometers shorter because its control systems and warhead are heavier.

United States officials have also accused Russia of seeking to undermine the treaty while painting Washington as the boogeyman who wants to destroy it. That sentiment is echoed by some analysts in Russia and elsewhere, while others suggested that American hard-liners feel constrained by the treaty.

At the time the pact was negotiated by the United States and the Soviet Union, the two superpowers had a near monopoly on such weapons, and the treaty led to the destruction of more than 2,000 of them.