At a press conference with his Bulgarian counterpart Georgi Parvanov in Sofia, Bush said he did not know if the proposal, aimed at defusing a Russian-U.S. row over U.S. missile-defense plans, was "technologically feasible," however.
Bush said he would like U.S. and Russian defense experts to hold meetings to discuss the matter.
Bush also reiterated that Kosovo ought to be independent from Serbia, saying that "the time is now to move the Ahtisaari plan," referring to the proposal by UN special envoy Martti Ahtisaari to give Kosovo a form of supervised independence.
In Albania on June 10, Bush said the United Nations should grant independence quickly to the Serbian province.
Russia, which has veto power on the UN Security Council, has joined its ally Serbia in opposing moves to grant Kosovo independence. Russia has called for more negotiations between Serbs and Kosovo's ethnic-Albanian majority.
In his comments in Albania, Bush said that "sooner rather than later," Kosovo needs to become independent.
Finally, Bush urged Libya to release five Bulgarian nurses sentenced to death for allegedly infecting hundreds of children with the virus that leads to AIDS. He said the release of the five was a "high priority" for the United States.
(with material from AFP, AP)