Defense Secretary Chuck Hagel said permanently stationing an additional U.S. Army brigade in Europe is among options to beef up security as Russian troops remain massed along Ukraine’s eastern border.

The North Atlantic Treaty Organization has asked its top military commander, U.S. Air Force General Philip Breedlove, to study “a number of new possibilities, new measures, new options that we and NATO should consider,” Hagel said in an interview today in Honolulu with Bloomberg News and Bloomberg Television.

Asked if those included permanently stationing a third brigade of 5,000 troops in Europe, Hagel said, “That’s all part of the measures that could be considered.”