Russia has test-launched a new intercontinental ballistic missile, Russian military officials say.
The launch took place at the Plesetsk cosmodrome in northern Russia at 1420 (1020 GMT) on Tuesday.
The missile, called RS-24, can be armed with up to 10 warheads and was designed to evade missile defence systems, the Russian defence ministry says.
Russia has complained that US plans to base parts of an anti-missile system in central Europe threaten its security.
The Americans maintain that their system is not directed at the Russians.
The US wants to deploy interceptor rockets in Poland and a radar base in the Czech Republic to counter what it describes as a potential threat from "rogue states" such as Iran and North Korea.
The Russian test missile successfully struck its target 5,500km (3,400 miles) away on the far eastern Kamchatka peninsula, the Russian Strategic Missile Forces said.
The statement said the missile would replace two ageing ICBM systems - the RS-18 and RS-20, known in the West as the SS-19 Stiletto and SS-18 Satan, respectively.
Our world affairs correspondent Paul Reynolds says the Russian missile test has more to do with Russia's plans to modernise its nuclear force than its complaints about the proposed US missile defence shield in Europe, which US officials say could not intercept Russian missiles.
Of particular concern to Russia is the treaty between the US and the then Soviet Union that banned intermediate range nuclear weapons, he writes. This treaty is still in force and applies only to the US and Russia.
Russian First Deputy Prime Minister Sergei Ivanov, quoted by Reuters on Tuesday, said the deployment of medium- and short-range missiles by Russia's neighbours to the east and south now posed a "real threat".
"The Soviet-American treaty (on intermediate nuclear forces) is not effective because since (its signature) scores of countries have appeared that have such missiles, while Russia and the United States are not allowed to have them," he told a military-industrial commission in the southern city of Znamensk.
"In these conditions, it is necessary to provide our troops with modern, high-precision weapons."