At least 13 people were killed Sunday in the Yemeni capital in a fresh bout of violence between forces loyal to President Ali Abdullah Saleh and his opponents, according to medical sources, DPA reported.
Six civilians were killed when pro-Saleh forces fired on protests who were marching from Change Square in Sana'a towards the president's palace, said opposition activists.
The protesters were chanting anti-Saleh slogans and demanding that United Nations pressure the Yemeni president to step down, they added.
Meanwhile, seven dissident soldiers were killed in clashes with pro-Saleh troops in Sana'a, according to the broadcaster Al Jazeera.
On Saturday, around 20 protesters were reportedly killed in Sana'a in an attack that the opposition blamed on Saleh's loyalists.
Disputing the casualty figures, Yemen's Deputy Information Minister Abdu al-Janadi Sunday accused opposition and "power seekers" of manipulating young people to trigger chaos and vandalize public and private properties in Sana'a.
The violence came as the UN Security Council was working on a draft resolution on the Yemeni crisis.
Millions of Yemenis have taken to the streets since February demanding Saleh's ouster.
At least 1,480 people had been killed in clashes between Saleh's loyalists and his opponents by the end of September, according to government figures.