CAIRO: The head of Egypt's influential seat of Islamic learning, al-Azhar, called on Tuesday for bold Arab action to stop the Syrian government's "hellish killing machine" while scolding China and Russia for blocking a peace plan in the U.N. Security Council.

Grand Imam Ahmed el-Tayeb, head of the Cairo-based institution, also urged Syrian protesters fighting Syrian President Bashar al-Assad to refrain from turning their struggle into an armed confrontation, two days after Arab League diplomats suggested arming opposition forces could be an option.

"The situation now, brothers, no longer needs statements to condemn and criticise, but it is in desperate need of urgent, serious, and bold action from the Arabs," Tayeb added, without giving details of what kind of action he sought.

"I call on the human conscience to stop this hellish killing machine that works to shed blood. It must be stopped."

Assad, whose Alawite-minority family has ruled the mainly Sunni Muslim Syria for 42 years, is trying to stamp out pro-democracy demonstrations and stop insurgent raids across Syria with what the U.N. rights chief described as indiscriminate attacks and shoot-to-kill orders.

Violence has escalated after a Russian and Chinese veto of a Security Council resolution that would have backed an Arab initiative calling for Assad to step aside and delegate powers to a deputy to begin dialogue with the opposition.

"The international conscience must be awoken in China and Russia," Tayeb said in a statement he read out by telephone to Egyptian state television.

Al-Azhar is a university and clerical body that has been a central seat of Sunni scholarship since the Middle Ages.

Observers and its own officials say it is seeking to develop a more active political role to make up for the lost time during ousted Egyptian President Hosni Mubarak's three-decades in power when the body kept close to the authorities.

Tayeb said the opposition had the right to defend themselves.

"Oh you in Syria standing on solid ground, be patient, be firm and continue on your path with the blessings of God and do not be drawn into violence or armed confrontation in this miserable, despicable struggle," he said.

"But do defend yourself, your property, your women and your children and know that anyone killed unjustly is a martyr."

Tayeb called on army officers in the Syrian government's forces to refuse orders to kill protesters, saying "remember that the mission of armies is to protect people and nations, not oppress".

He also said the body would be willing to go to Syria to end the dispute, if "the path was opened for it".

While the uprising initially involved rallies by civilians, armed insurrection by the Free Syrian Army, made up largely of army defectors, is increasingly coming into play.

Assad dismisses his opponents as terrorists backed by enemy nations in a regional power-play and says he will introduce reforms on his own terms.