UN Secretary-General Ban Ki-moon today said the United Nations is optimistic about the talks of a new strategic arms reduction treaty (START) between Russia and the United States.<br/><br/>The UN Chief, who arrived in Moscow for a working visit, said if US and Russia sign a new START treaty, it would be very important and positive for the upcoming Nuclear Security Summit slated for April 12 and 13 in Washington and the Review Conference on the Nuclear Non-Proliferation Treaty in New York in May. <br/><br/>Mr. Ban Ki Moon is scheduled to attend a meeting of the Middle East quartet in Moscow tomorrow and meet Russian leaders on global hotspot issues.<br/>