Yemeni authorities stepped up security in the capital Sanaa on Friday ahead of rival rallies between government supporters and opponents.
Thousands of protesters calling for an end to President Ali Abdullah Saleh's 32-year rule have been holding a sit-in outside Sanaa University, while his supporters have rallied in another part of the capital.
Seventeen people have died in the past nine days in a sustained wave of nationwide anti-Saleh protests galvanised by the fall of the Tunisian and Egyptian presidents. Saleh has said he will not give in to "anarchy and killing".
Witnesses said police in Sanaa had formed cordons round the rival groups of protesters and supporters, whose numbers were expected to swell after Friday prayers, to prevent either side from confronting the other.
A statement from the Yemeni embassy in Washington said Saleh had demanded security services offer "full protection" for the demonstrators and prevent direct confrontations.
"Furthermore, the government calls on protesters to remain vigilant and take all precautionary steps to prevent the infiltrations of individuals seeking to carry out violent actions," the statement said.
State news agency Saba said Saleh has also assigned a committee headed by Prime Minister Ali Mohammed Megawar to open a dialogue with protesters to hear their demands.
AgenciesGüncelleme Tarihi: 25 Şubat 2011, 11:59