BRUSSELS, Belgium - U.S. and NATO officials said Thursday that they expect the military alliance to formally participate in the Obama administration's plan for a missile defense shield over Europe, scheduled to be activated next year. 'Based on today's discussion, I am quite optimistic,' NATO Secretary General Anders Fogh Rasmussen told reporters after a joint meeting of foreign and defense ministers from the alliance membership. 'There is, I think, a broad agreement that we should make such a decision, but there is still some technical work to do.' NATO is scheduled to vote at a summit in Lisbon, Portugal, next month on whether to make missile defense a formal part of its mission. If it does, European alliance members would plug their individual defense systems into a broader missile shield that the Obama administration is building to guard against potential attacks from Iran. The United States would foot most of the bill for building and operating the shield over Europe. The combined cost for other NATO members to link into the system is projected to be about $200 million over 10 years, Rasmussen said. Although U.S. and NATO officials said they are close to a consensus on missile defense, there are still hurdles to overcome. Turkey, a NATO member and neighbor of Iran that would host a key anti-missile radar installation, has yet to commit. Defense Secretary Robert Gates and Secretary of State Hillary Rodham Clinton met with their Turkish counterparts on the sidelines of the NATO meeting Thursday to discuss whether Turkey will allow a high-powered X-band radar on its territory. The location of the radar is the last unresolved piece in the first phase of the Pentagon's missile defense shield for Europe. 'I would say that we are not putting pressure on the Turks, but we are having continuing conversations with them as one of our allies,' Gates said at a news conference in Brussels. Although Turkey is a longtime NATO member, its government has developed closer ties with Iran in recent years and appears reluctant to take steps that Tehran might consider hostile. Turkish officials have also sought guarantees that the anti-missile shield would cover the eastern part of their country, which borders Iran. Pentagon officials are seeking Turkey's agreement to host the radar installation but also to vote in favor of missile defense as a NATO mission at next month's summit. Because NATO operates by consensus, Turkish opposition could scuttle the alliance's plans. 'We've had some very good, deep discussions with Turkey, and now the decisions are in Ankara to make,' Jim Townsend Jr., deputy assistant secretary of defense for European and NATO policy, told reporters in Washington on Tuesday. Pentagon officials said they have been negotiating with other NATO allies in southern Europe to host the radar in case Turkey balks. One alternative is Bulgaria, which like Turkey borders the Black Sea but is farther from Iran. The radar installation - along with mobile radars deployed on Navy ships in the Mediterranean and Black seas - would provide a critical early warning of any launches from Iran, improving the odds of shooting down a missile. Obama announced in September 2009 that he was overhauling the Bush administration's plans for missile defense in Europe. Although Obama had previously expressed skepticism of Bush's approach, he directed the Pentagon to build a more extensive and flexible missile shield for Europe that will be built in phases between now and 2020. 