Yemeni President Ali Abdullah Saleh declared a nationwide state of emergency Friday, after dozens of people were killed at an anti-government protest in the capital, Sana'a.
He made the announcement after security forces and government loyalists opened fire on protesters who were gathering in a square in Sana'a. Medical officials and witnesses say at least 40 people were killed and more than 100 wounded.
Witnesses say some gunmen opened fire from rooftops when thousands of demonstrators calling for an end to Mr. Saleh's 32-year rule poured onto the streets after Friday prayers. Anti-government protests erupted in other cities, Friday, including Taiz and Aden.
World powers are criticizing the violence. U.N. Secretary-General Ban Ki-moon condemned the government's use of live ammunition on protesters and said he is "deeply troubled" by Yemen's continued violence and instability.
EU foreign policy chief Catherine Ashton said she is "dismayed" by reports coming from Yemen. She urged President Saleh to stop the violence. U.S. President Barack Obama also condemned the unrest and said those responsible for Friday's violence must be held accountable.
Friday's unrest follows clashes on Thursday, when at least 85 people were reported wounded after Yemeni security forces and government loyalists clashed with protesters.
Yemenis angered by poverty, corruption and a lack of political freedoms began demonstrations earlier this year.
Mr. Saleh also faces a challenge to his authority from al-Qaida militants, who have based themselves in lawless parts of Yemen to plot attacks on the government and the West.
Some information for this report was provided by AP, AFP and Reuters.