TUNIS, Tunisia — Unrest engulfed Tunisia on Saturday after a popular rebellion forced the president to flee: Dozens of inmates were killed in two prison fires, looters emptied shops and torched the main train station and gunfire echoed through the capital.

Power changed hands for the second time in 24 hours in this North African country after President Zine El Abidine Ben Ali fled the country Friday for Saudi Arabia. The head of the Constitutional Court declared Saturday that Ben Ali has left office for good — not temporarily — and rejected the prime minister’s move to assume power.

The speaker of the lower house of parliament, Fouad Mebazaa, took the highest office instead, and was given two months to organize new elections.

Anger over corruption and the lack of jobs ignited a month of protests, but Ben Ali’s departure — a key demand of demonstrators — has not calmed the unrest. While the protests were mostly peaceful, after Ben Ali’s departure rioters burned the main train station in Tunis and looted shops.

Sporadic gunfire was heard in the capital of Tunis on Saturday. Smoke billowed over a giant supermarket outside the capital as looters torched and emptied it. Soldiers fired warning shots to little avail.

Saudi King Abdullah’s palace confirmed Saturday that the ousted president and his family had landed in Saudi Arabia, saying the kingdom welcomed him with a wish for “peace and security to return to the people of Tunisia.”