James Appathurai, speaking after the opening of the annual NATO defense ministers' meeting in Brussels on June 14, said all NATO ministers wanted to avoid tensions and do everything possible to allay Russian concerns.
The U.S. choice of Poland and the Czech Republic as sites for its missile-defense installations has angered Moscow.
But Russian President Vladimir Putin last week suggested his concerns could be met if the United States moved the installations from Central Europe to Azerbaijan.
NATO spokesman Appathurai praised Putin's initiative as a "step forward" and an attempt to reduce tensions. He also said it was an acknowledgement of the threat from Iran Washington cites as a reason it needs the missile shield.
NATO Secretary-General Jaap de Hoop Scheffer told journalists this afternoon that because the U.S. missile shield will not cover all of NATO's allies, the alliance will start studying the possibility of complementing it with its own defense systems.
De Hoop Scheffer said NATO's defense ministers will return to the issue at their next meeting in February 2008 and that a final decision would be taken by alliance leaders at their summit in Bucharest in the spring of 2008.
NATO's chief underscored that the alliance is already cooperating with Russia on theater missile issues, but did not elaborate on possible Russian participation in NATO's new plans.
NATO officials praised U.S. efforts to reach out to Moscow over missile defense. Spokesman Appathurai said the United States is ready to share intelligence and technology, and also said Washington itself has in the past raised the possibility of jointly using the radar base in Azerbaijan.
However, de Hoop Scheffer said after meeting with Russian Defense Minister Anatoly Serdyukov that he doesn't think that Putin's offer of the use of the Azerbaijani radar site will replace, or be an alternative to, current U.S. plans to deploy parts of the system in Poland and the Czech Republic.
Appathurai also said the NATO ministers this morning had also extensively discussed an Estonian request to step up the alliance's cyberdefense capabilities.
This spring, Estonia came under extensive cyberattacks, which disabled numerous government and private websites. The Estonian government has said the attacks were instigated by Moscow in retaliation for the removal of a Soviet World War II monument from central Tallinn in late April.
NATO ministers adopted a declaration promising "urgent action" to enhance the protection of the alliance's "critical infrastructure."
Estonian Defense Minister Jaak Aaviksoo explained to RFE/RL the direction Estonia is expecting NATO to take in its efforts.
"The first is setting up relevant structures tasked with tackling this issue. Some of it will probably take the form of drawing conclusions from the Estonian experience. The other issue has to do with giving formulation to the challenges that arise within the context of cyberattacks. What is a cyberattack, for example? What's the difference between a cyberattack and cyberwar? How would nations need to respond to computers on their territory being used in attacks against another country? Do nations have the right of locating such computers and taking them offline?" Aaviksoo said.
The NATO defense ministers also met their Ukrainian and Russian counterparts on June 14.
Officials said ahead of the meeting with the Defense Minister Serdyukov that missile-defense issues, Kosovo, and cooperation with regard to Afghanistan would dominate the meeting's agenda.
NATO ministers were also scheduled to discuss the alliance's work in Afghanistan.
On June 15, ministers will hold talks with the Afghan Defense Minister Abdul Rahim Wardak.