The United States has repeatedly rejected Russian demands to freeze U.S. negotiations with Poland and the Czech Republic, and Rice did so again Friday, said three senior U.S. officials present at the sessions with Rice, Gates, Russian Foreign Minister Sergey Lavrov and Defense Minister Anatoly Serdyukov.Turkey -- now a NATO member and a key U.S. ally in the war on terror -- accepts Armenians were killed but calls it a massacre during a chaotic time, not an organized campaign of genocide."Events have triggered more detailed planning for the curtailment or closure" of access to Turkey, one official said. The key issue is to find ways to ship supplies and other critical equipment into Iraq.U.S. military planners quietly have stepped up a review of alternatives in case the Turkish government restricts U.S. access to Turkish airspace or cuts off access to the air base at Incirlik, Turkey, CNN has learned.Meanwhile, two U.S. soldiers were killed and five others were wounded in a mortar attack launched "in the vicinity of Baghdad" on Wednesday, the U.S. military said Saturday. The deaths put the total number of U.S. military personnel killed in the Iraq war at 3,827.Initial reaction from Lavrov and Serdyukov, though, was less gracious.The officials, who spoke on condition of anonymity to describe diplomatic discussions, maintained that differences were narrowed but progress was incremental and might not produce ultimate understandings.The U.S. military already had been considering alternatives to Turkey because of the growing dependence on that country after the cutback of U.S. forces in central Asia in recent years."We hope that in the process of such complex and multifaceted talks you will not be forcing forward your previous agreements with Eastern European countries," Putin said.The U.S. proposals are intended to ease fears that its missile defense plans threaten Russia's nuclear deterrent and include the creation of a so-called joint regional missile defense architecture to protect the United States, NATO allies in Europe and Russia.