WASHINGTON (Reuters) – The top U.S. military officer, General Mark Milley, spoke by telephone with Russia’s Chief of General Staff Valery Gerasimov, the Pentagon said on Thursday, the first conversation between the two since Russia’s invasion of Ukraine in February. “The military leaders discussed several security-related issues of concern and agreed to keep the lines of communication open,” said a spokesman for Milley, the chairman of the U.S. Joint Chiefs of Staff. “In accordance with past practice, the specific details of their conversation will be kept private,” the spokesman added. The U….