Senior US and Russian officials have held two days of talks in Washington on controversial US plans to base a missile-defence system in Eastern Europe, partly focusing on how the two sides can cooperate in addressing ballistic missile threats from rogue nations, the US State Department said Wednesday, "They had a good preliminary exchange on the issues, looking at the perspectives of both sides on the threat to proliferation from ballistic missiles and" weapons of mass destruction, State Department deputy spokesman Tom Casey said. US President George W Bush and Russian President Vladimir Putin agreed to arrange the discussions during a summit in Kennebunkport, Maine, in July to try to overcome stark differences on the plans for 10 missile interceptors in Poland and a radar station in the Czech Republic. The dispute between the two countries has sparked some of the harshest rhetoric since the Cold War and concerns of rekindling an arms race. Russia believes the defence shield is a threat to its own national security, while the United States insists it is designed to counter Iran's growing ballistic missile capability. Putin has proposed using a Russian site in Azerbaijan instead of deploying to Eastern Europe. Bush considers the proposal interesting but says it cannot be a substitute for the locations in Poland and the Czech Republic. The Russian officials provided more information on the Azerbaijan proposal, Casey said. Russian Deputy Foreign Minister Sergei Kislyak led his country's delegation, which met with with US assistant secretaries of state Daniel Fried and John Rood, and US Defence Undersecretary Eric Edelman for the "expert level" talks. "It was a chance for both delegations, really though, to give their perspectives on the threat as we saw it from the United States to Europe and to Russia," Casey said. The two sides have planned further meetings to address the issue. US Secretary of State Condoleezza Rice and Defence Secretary Robert Gates plan to hold a combined meeting with their Russian counterparts this fall.