Russia and the U.S. have reached a preliminary deal to reduce their respective stockpiles of nuclear weapons. The deal comes shortly after U.S. President Barack Obama landed in Russia for his first since his inauguration in January. The scope of the agreement is modest: it calls for negotiators to strike a deal that would see the number of nuclear warheads on each side reduced to between 1,500 and 1,675, rather than the 2,200 agreed to under the Treaty of Moscow. Still, it is expected to serve as groundwork for future agreements that call for deeper cuts to each country’s arsenal. Russia and the U.S. nonetheless remain sharply divided over U.S. plans to implement an elaborate missile defense system Russia claims is a threat to its territory.