Vienna ? The United States has agreed to notify other nations before it launches most ballistic missile tests or satellites, in a measure that builds on a landmark arms agreement with Russia and is meant to encourage Moscow to reciprocate.

The American decision was contained in a confidential note made available Thursday to The Associated Press and confirmed by three diplomats familiar with the issue.

The move is less far-reaching — or binding — than the treaty signed last month by the U.S. and Russian presidents that outlines cuts in both nations’ massive nuclear arsenals. But it is significant in reflecting Washington’s determination to build on the success of that agreement.

For years, Russia voluntarily provided such pre-notifications regarding the launch of ballistic missile tests or satellites. But it stopped doing that two years ago, complaining that the U.S. and other nations were not following suit.