Russian President Dmitry Medvedev says that the United States and NATO should come up with an alternative missile defense plans that will not jeopardize nuclear parity with Moscow. Washington says the NATO missile defense plan is aimed at potential missile threats from nations such as Iran. But Moscow fears it will eventually grow powerful enough to intercept Russian missiles, thus undermining its nuclear deterrent. Medvedev said Friday that \"we are ready to discuss alternative ideas,\" but complained that the West offered \"none.\" However, he assured an international security conference that \"no doors have been shut\" in the Russian-Western dialogue over the missiles. NATO has said it wants to cooperate with Russia on the missile shield. But it has rejected Russia\'s proposal to run the shield jointly.