MOSCOW (AP) — Russian and U.S. negotiators discussed the expiration of the last remaining nuclear arms pact between the two countries and agreed on the need to quickly launch new arms control talks, the Kremlin said Friday. The New START treaty terminated Thursday, leaving no caps on the two largest atomic arsenals for the first time in more than a half-century and fueling fears of an unconstrained nuclear arms race . Russian and U.S. negotiators discussed the issue in the United Arab Emirates,