RAS LANUF, Libya — Government warplanes taunted rebels with flyovers and repeatedly bombed their positions near this coastal city’s oil refinery on Monday, seeking to drive the opposition forces back farther to the east, as Libya continued what appeared to be a slide into civil war.

The air attacks, which wounded a family of five, added a note of urgency to a growing debate in Western capitals about imposing a no-fly zone over Libya.

The bombing runs began in the morning, sending huge plumes of smoke into the air around 10 a.m. With every roar of a jet engine, the rebels opened fire with what sounded like every weapon available, from heavy artillery to pistols. In the evening, a warplane swooped low and on two separate occasions dropped bombs near a heavily defended rebel checkpoint, striking a car carrying the family and sending rebel fighters fleeing for cover in chaotic scenes.