An outlaw band headed by three crafty brothers has badly shaken Peru's government by mounting hit-and-run attacks that leave little doubt: A retooled and well-disciplined Shining Path rebel force has taken firm root in the world's leading cocaine-producing valley.

The Quispe Palomino brothers, who command about 500 combatants, solidified their reputation with last month's abduction of 36 construction workers near Peru's main natural gas fields. The guerrillas then killed eight soldiers and police sent to rescue the workers in a fiasco that cost the defense and interior ministers their jobs.

"The Quispe Palomino band remains a very potent, violent, mobile and resilient force," said analyst Diego Moya-Ocampos, with the IHS-Jane's Information Group in London.

The very idea of a well-armed, resurgent Shining Path, fortified by cocaine wealth, stirs deep-seated fears in Peruvians who endured the terror of the once-powerful movement two decades ago.