On a dusty parade ground outside Tripoli, young recruits march and bark out slogans for the new Libyan army that Western powers hope can turn the tide on militias threatening to engulf the North African country in anarchy.

Their boots are new and their fatigues pressed, but Libya’s army recruits will need more than drills to take on the hardened militiamen, Islamist fighters and political rivalries testing their OPEC nation’s stability.

Two years after NATO missiles helped rebels drive out Muammar Gaddafi, Libya is under siege from former rebel fighters who now flex their military muscle to make demands on the state, seize oilfields and squabble over post-war spoils. […]