The Obama administration signed accords this week with three NATO allies to host cornerstones of a missile shield over Europe, including a highly sought-after deal with Turkey that will allow the installation of a U.S. radar station close to Iran.

After nearly two years of talks with Washington, Turkey’s Foreign Ministry announced Wednesday that it would allow the U.S. military to operate a high-powered X-band radar station in Malatya province, about 400 miles west of the Iranian border. Along with similar radars deployed on U.S. Navy ships in the Mediterranean Sea, the station is intended to provide early warning of missile launches from Iran.

Turkey signed the agreement despite heavy political pressure from Iran and another neighbor, Russia, which have criticized the missile shield as a stalking horse to neutralize their own defenses. Iran’s Foreign Ministry assailed Turkey’s decision, saying it would “create tension” and cause “complicated consequences.”

Turkey has sought to maintain friendly relations with Russia and Iran under its self-described “no problems with neighbors” policy. In this instance, however, the government in Ankara sided with the United States and its other NATO allies. Turkey has been a member of the military alliance since 1952.

Obama administration officials portrayed the radar accord as a coup not only for their missile defense plans but also their efforts to bolster ties with Turkey, which had soured because of the U.S.-led invasion of Iraq in 2003.

“This is probably the biggest strategic decision between the U.S. and Turkey over the past 10 to 15 years,” a senior Obama administration official said Thursday, speaking on the condition of anonymity to discuss details of the negotiations.

With a booming economy, Turkey has become an increasingly influential force in diplomatic and business circles in the greater Middle East. In recent years, however, Turkey has burnished ties with Iran and Syria while cooling toward Europe, prompting concern in Washington.

Turkey’s deteriorating relations with Israel posed another hurdle in the talks with Washington.

Turkish officials had insisted that the U.S. military not share data from the radar with Israel, which sees itself at much higher risk of an Iranian missile attack. Turkey’s stance raised hackles on Capitol Hill, however, where several senators urged the White House to reject such restrictions.

Another senior administration official, also speaking on the condition of anonymity, said the signed agreement with Turkey does not bar the United States from indirectly providing radar data to Israel.

“It’s understood that data from any U.S. radars and sensors around the world may be fused with other data to maximize the effectiveness of our missile defenses worldwide,” that official said. “Nothing in any of the agreements restricts our ability to defend the state of Israel.”

Although the early-warning radar in Turkey will primarily support NATO’s missile defenses in Europe, the station will be owned and operated by the U.S. government. The U.S. military operates a similar radar station in Israel and is looking to place another near the Persian Gulf.

Administration officials said there was “no quid pro quo” as part of the Turkey radar agreement. The United States and Turkey are holding separate talks over basing U.S. drones in Turkey to guide attacks against Kurdish militants — a high priority for Ankara.

Development of a European missile shield accelerated under the George W. Bush administration. In September 2009, President Obama announced plans to construct a more extensive system in Europe that will be built in phases through 2020.

Under that system, a total of 48 missile interceptors will be based in Romania and Poland, starting in 2015 and 2018, respectively. The State Department finalized agreements with those countries this week.

At the same time, the Obama administration and NATO have been talking with Russia about the possibility of cooperating on missile defense. Moscow has been historically hostile to the idea of a missile shield in Europe, and the discussions have slowed recently.

“Our bilateral dialogue with Washington, and with Brussels within the NATO framework, has been increasingly stalled,” said Alexander Lukashevich, a Foreign Ministry press spokesman, according to the Interfax news agency.

Correspondent Will Englund in Moscow contributed to this report.