In Yemen police have killed two children and hundreds of people have been wounded in clashes in the capital Sanaa and the southern city of Mukalla.
On Saturday security forces fought protesters in the capital in an attempt to prevent the spread of a makeshift camp housing thousands of government opponents.
At least 30 people have lost their lives in weeks of unrest in the poverty-stricken country. The protesters are demanding an end of the 32 year rule of President Ali Abdulla Saleh.
The Interior Ministry accused demonstrators of opening fire on police, claiming 161 officers had been injured. The spokesman also denied police had used any kind of nerve gas on protesters.