Russian Prime Minister Vladmir Putin says American plans for a missile defence system are holding up completion of a new nuclear arms reduction treaty.
Mr Putin says a US missile shield could force Russia to develop new offensive weapons systems.
The US State Department says the planned missile defence system and the completion of a new nuclear arms treaty are completely separate issues.
In a statement, the department says the US will continue to discuss the topic of missile defence with Russia.
The United States has scrapped plans for a land based missile shield in Europe and but intends to use a sea-based system.
