The U.S. government on Tuesday in its annual report on arms control compliance publicly accused Russia of violating the bilateral treaty on nonproliferation of medium-range nuclear missiles.

The report says that Russia violated its obligations under the Intermediate-Range Nuclear Forces Treaty not to "possess, produce or flight-test" land-based cruise missiles with ranges between 500 and 5,500 kilometers (310 to 3,410 miles) or to possess and produce the launchers for those missiles.

According to intelligence sources, Russia may have been developing new medium-range missile technology, which would be a clear violation of the 1987 INF Treaty to eliminate short- and medium-range nuclear missiles signed by then-U.S. President Ronald Reagan and the head of the now defunct Soviet Union, Mikhail Gorbachev.

"This is a very serious matter which we have attempted to address with Russia for some time now," a top State Department official said, requesting anonymity.

"The United States is committed to the viability of the INF Treaty. We encourage Russia to return to compliance with its obligations under the Treaty and to eliminate any prohibited items in a verifiable manner," said the official.

The State Department said that the U.S. government will consult with its allies and "take into account the impact of this Russian violation on our collective security if Russia does not return to compliance."

The United States noted that the INF Treaty is essential for guaranteeing security in Europe and East Asia.

The accusation comes at a moment of high tension between Washington and Moscow over the crisis in Ukraine, where pro-Russian separatists in two eastern regions of the country are refusing to acknowledge the authority of the new pro-Western government in Kiev and are being armed by Moscow, Washington says.

In addition, tension has ratcheted up several notches with the shootdown of a Malaysian Airlines flight - apparently by a Russian-supplied ground-to-air missile that Washington says was fired by separatists in eastern Ukraine. All 298 people on board the plane were killed.

The United States also accuses Russia of firing short-range rockets and artillery barrages from its territory onto Ukrainian army positions in the adjacent country.

The United States and Europe already had imposed sanctions on Russian President Vladimir Putin's inner circle.

Meanwhile, U.S. President Barack Obama on Tuesday announced a third round of sanctions against Russia for its continuing support for the activities of pro-Russian rebels in Ukraine and he warned that the costs will continue increasing if Moscow does not change its current path.

This is the third package of economic sanctions imposed on Moscow and the new measures affect the energy, defense and financial sector.

The announcement comes just hours after the European Union on Tuesday also adopted further sanctions against Russia and the president said the measures were taken in a coordinated manner so that they might have an "even bigger bite."

The targets of the sanctions are three state-run Russian banks - VTB Bank, the Bank of Moscow and the Russian Agricultural Bank - which will now have their access curtailed to short- and long-term capital markets in dollars, the U.S. Treasury Department said in a communique.

In addition, the sanctions are being imposed against the United Shipbuilding Corp., one of Moscow's main military construction firms, and they prohibit exports to Russia of oil production and exploration equipment.

The president said that "this is a choice that Russia and President Putin in particular have made," adding that the sanctions are not designed to start "a new Cold War," but rather are a way to get Moscow to let Ukraine select its own economic and political path. EFE