Saleh’s forces fired on protesters in the southern city of Taiz on Thursday, reports said.

The protesters were demanding the end of President Ali Abdullah Saleh’s 33-year-rule over the impoverished Arab state.

Yemeni soldiers opened fire on protesters, Reuters reported quoting witnesses. There have been no reports of immediate deaths or injuries.

Earlier this week, the U.N. human rights representative said her office was investigating reports that Yemeni soldiers have killed at least 50 protesters in Taiz since Sunday.