Damascus: The Arab League on Friday served Syria notice to endorse a plan for the dispatch of observers to monitor unrest in the country or face crippling sanctions.
Activists called for a new day of anti-regime protests, urging demonstrators to flood the streets nationwide after the main weekly Muslim prayers in support of dissident army officers.
"The free army protects us," said a message on the Facebook page of the Syrian Revolution 2011, one of the key motors behind more than eight months of protests seeking to unseat the government of President Bashar al-Assad.
"The free army is the guardian of our peaceful revolution," it said, in reference to the rebel Free Syrian Army which has claimed numerous attacks on regular troops in recent weeks.
At least 51 people were killed in violence across Syria Thursday, including 23 regular army soldiers and 15 deserters, according to the Britain-based Syrian Observatory for Human Rights.
Thirteen civilians also died, 12 of them in the flashpoint protest hub of Homs, the group said.    

The Arab ultimatum was issued Thursday at the end of a crisis meeting of foreign ministers in Cairo, during which the 22-member bloc also for the first time called on the United Nations to help resolve the crisis.
Long resistant to drawing the international community into the Syria crisis, the League agreed to ask UN Secretary General Ban Ki-moon "to take all measures to support the efforts of the Arab League to resolve the critical situation in Syria."