These capabilities would range from cyber to drones to long-range mobile communications and non-lethal weapons as well as small arms, explosives, anti-tank and anti-aircraft weapons, the Rand Corporation report said.

"Total defense and unconventional warfare capabilities can complement the existing conventional defense efforts of the Baltic states and NATO," said Stephen Flanagan, the report's lead author.

He said such cells would also buy time for national and NATO responses if Russia did invade one or all of the tiny republics on its western border, as it did with Crimea in 2014.

NATO members since 2004, the Baltic states, which like Ukraine have an ethnic Russian minority, are already in the process of building up its special forces units.

The report called for strengthened cooperation between the Baltic states, the European Union and NATO in areas such as crisis management, intelligence, resistance and fighting disinformation.

The idea proposed by the report's authors would be to organize each Baltic country's defenses around four levels of resistance.

"Violent" units made up of special forces, reservists and undefeated combat units would be charged with carrying out ambushes or freeing prisoners, under the scheme outlined in the report.

Less heavily equipped units composed of police or amateur sharpshooters would be in charge of sabotage operations.

Civilians would be looked to for intelligence support, to care for the wounded and feed combatants.

The report recommends supplying the Baltic states with night-vision goggles, portable computers, cameras and all-terrain vehicles as part of a program estimated to cost an initial $125 million.