CAIRO (AP) — Hundreds of demonstrators are gathering in different Sudanese cities, protesting against autocratic President Omar al-Bashir.

Tuesday's demonstrations were called by the Sudanese Professionals Association, an umbrella of independent professional unions.

Video footage shows demonstrators gathering at intersections chanting "just fall," and calling for a "people's revolution."

The current wave of protests began Dec. 19, initially over surging prices and a failing economy, but quickly shifted to calls for an end to al-Bashir's three-decade rule.

Al-Bashir, who seized power in a military coup, insists that only elections, which he intends to run in, could bring change.

Activists say at least 57 people have been killed in the protests. The government's latest tally stands at 30 killed, but figures have not been updated in days.