Bush and Putin Agree to Reduce Stockpile of Nuclear Warheads
Pres Bush and Russian Pres Vladimir V Putin separately vow deep cuts in their nuclear stockpiles over next decade that would leave each side with fewer than 2,200 warheads; Putin calls for written accord, move Bush wants to avoid, news conference, Washington; two nations still seem far apart on missile defenses, with Putin apparently resisting United States bid for quick accord to ease ABM Treaty, meeting with Bush; Bush and Putin stress emergence of US and Russia as allies, news conference; Bush pledges to speed through Congress bill to take Russia and other former Soviet republics off list of nations subject to economic sanctions; much of their four-hour meeting focuses on Afghanistan; Putin suggests joint consulations and action on terrorism of last two months are model for new military ties with US and NATO; photos (M)