Haitians are no strangers to hunger. But even the resilience of the hemisphere's poorest citizens can be pushed too far, and with world food prices spiking this year due to shrinking harvests, burgeoning demand and skyrocketing fuel prices, it should be little surprise that Haiti is once again erupting in angry violence.

As unrest spread from the countryside, protesters shut down the capital, Port-au-Prince, on Tuesday to decry lavi che — the Creole term for the high cost of living. Gunshot wounds have killed several people this week and injured a Haitian journalist. Rioters broke down two gates to the National Palace before they were stopped by United Nations peacekeepers; Haitian National Police, who number around 8,000, are securing government buildings but have not yet been able to dismantle the barricades of rocks and burning tires that have closed off most of the major roads.

All businesses, schools and government activities have ground to a halt, reminiscent of bloody protests that have plagued this country for the last several decades — most recently in 2004, when former President Jean-Bertrand Aristide was overthrown. President Rene Preval, respected for his probity but criticized for his lack of leadership and statesmanship, has been trying to improve Haiti's squalid conditions since taking office in 2006, but demonstrators squeezed by spiraling food costs say they're tired of waiting for a solution to their constant hunger. "We used to be hungry enough to drink Clorox," a local mechanic told TIME by phone from Port-au-Prince. "Now it's battery acid — it gets the job done quicker." Last week, Preval had said he understood the frustrations, and quipped that if people started to protest, they should stop by the palace and pick him up. In an ironic twist, that may have prompted them to break into the palace Monday. Preval did not join the protesters, and he's yet to say anything publicly since then.