MOSCOW — Russia said that new submarines will be armed with improved nuclear-tipped cruise missiles, a state-connected news agency reported Friday.

ITAR-Tass quoted the Defense Ministry as saying that the first in a series of six atomic submarines, the Severodvinsk, will join the navy in 2011. At least five other submarines of the same type will be built by 2017, it said.

The new hypersonic cruise missiles with increased range are designed to strike "aircraft carriers of the potential enemy if they pose a direct threat to Russia's security," the ministry said, according to ITAR-Tass. It said the missiles are also capable of hitting land targets.

A Defense Ministry spokesman would not comment on the report.

Russia has increasingly relied on nuclear weapons to compensate for the decline of its conventional forces.

In December, the chief of the Russian military's general staff, Gen. Nikolai Makarov, said Russia will keep its arsenal of tactical nuclear weapons, which he said were necessary to counter a massive NATO advantage in conventional weapons.

Tactical nuclear weapons have a much shorter range compared to strategic nuclear weapons. They are intended for use within a theater of battle.

The United States and the Soviet Union decided in 1991 to eliminate some of their non-strategic nuclear weapons and withdraw others from duty, including those used by navy ships.

But in 2006, Russia signaled it no longer intended to abide by that decision when then-Defense Minister Sergei Ivanov said that Russian submarines were carrying tactical nuclear weapons on patrol.

Earlier this week, the Russian navy's deputy chief of staff said the role of tactical nuclear weapons in the Russian navy may grow. Vice Adm. Oleg Burtsev said the increasing range and precision of tactical nuclear weapons makes them an important asset.