Estonia's President Toomas Hendrik Ilves has called for a permanent NATO force to be stationed in his country.
Ilves told Britain's Daily Telegraph newspaper that Estonia was "part of a group of countries who are mentioned in a threatening way" by Russia.
A U.S. infantry company numbering 150 soldiers is currently NATO's only presence in Estonia, but it is not permanent.
Ilves said 150 soldiers "is not a lot, so we do think that further stationing of troops at a higher number is only reasonable."
Russian military maneuvers on Estonia's border have triggered concern in Europe that Moscow could attempt to destabilize its bordering countries.
NATO has pledged a 5,000-strong task force and command centers in six former Soviet republics, including one in Estonia.
Estonia joined NATO in 2004.