Backgrounder: US missile defense in Europe

The US claims the plan to set up a missile defense system in east Europe was to counter Tehran's emerging long-range-missile program. Russia thought it threatened its national security and strongly opposed it. The plan also become an important factor in Russia-US relations.

Under the US plan, 10 ground base interceptors are to be installed in northern Poland and will include a radar system in the Czech Republic.

The US claims the plan is to counter potential threats from countries like Iran.

Poland and the US have been in secret contact on the strategic missile defense base.

The negotiations stalled for different reasons and was resumed in 2007. The US signed agreements with Poland and the Czech Republic separately.

The U.S. plan infuriated Russia, which deems it a serious threat to its national security. In 2007, Russia announced it suspended the Europe Arms Treaty and started to upgrade a new series of strategic arms.

In November 2008, Russian President Dimitry Medvedev announced Russia would deploy a short-range missile system in its Baltic enclave of Kaliningrad bordering Poland in response to the U.S. plan.

On March 6th, Medvedev said Russia would like to participate in a missile defense system that would counter any threats but is opposed to set up anti-missile systems near Russian borders.

On March 2nd, Russian state media reported US President Barack Obama sent a secret letter to Medvedev persuading Russia to help solve the Iran nuclear issue and in exchange, the US would give up the missile defense system in east Europe.