SANAA, Yemen - Tens of thousands of people are gathering in a main square in the Yemeni capital for Friday prayers that are expected to be followed by mass protests to press demands for the president to step down.

Witnesses say the protesters are pouring into a square near the main gates of Sanaa University for the demonstrations amid a tight security presence.

Yemen has been swept up in protests inspired by the recent successful uprisings in Egypt and Tunisia. The demonstrators are demanding that U.S.-backed President Ali Abdullah Saleh, in power for 32 years, step down.

On Wednesday, Saleh said he had ordered his security services to protect protesters, stop all clashes and prevent direct confrontation between government supporters and opponents.