US Secretary for Defense Donald Rumsfeld is to come on a working visit to Moscow on Saturday. The principal aim of Rumsfeld's trip is the preparation for Russian President Vladimir Putin's official visit to the USA scheduled for mid-November, informed military-diplomatic sources in Moscow told RIA Novosti. According to the sources, the US Secretary is to discuss with Russian top officials the key issues of the Russian-American relations, firstly, the problems of the ABM Treaty and further strategic nuclear arms reduction. In this connection the sources do not rule out the reaching of an agreement on the amount of strategic nuclear weapons each side will have after the reductions. In addition, the Pentagon head will discuss the course of the anti-terrorist operation in Afghanistan with the Russian side, the sources said.