By Khaled Yacoub Oweis

DAMASCUS (Reuters) – The Muslim Brotherhood called on Syrians to take to the streets ahead of Friday prayers and help the besieged city of Deraa, where a rights group said civilian deaths from a tank-backed army attack rose to 50.
It was the first time that the Brotherhood, ruthlessly crushed along with secular leftist movements under the rule of late President Hafez al-Assad, had called directly for protests in Syria since pro-democracy demonstrations against Assad's son, President Bashar al-Assad, erupted six weeks ago.
A declaration by the Brotherhood, sent to Reuters by its leadership in exile Thursday, said: "Do not let the regime besiege your compatriots. Chant with one voice for freedom and dignity. Do not allow the tyrant to enslave you. God is great."
The protests have drawn a cross section of Syrian society, which has been under Baath Party rule for the last 48 years. The younger Assad kept intact the autocratic political system he inherited in 2000 while the family expanded its control over Syria's struggling economy.
The Brotherhood said accusations by the authorities that militant Islamists were behind the unrest were aimed at fomenting civil war and undermining nationwide demands for political freedoms and an end to corruption.
But Friday, the Muslim day of rest and prayers, has been the main opportunity for protesters to gather, challenging repeated warnings by the authorities not to demonstrate.
Security forces shot dead at least 120 protesters last Friday, said Syrian human rights organization Sawasiah, in the biggest demonstrations Syria has seen since the democratic uprising erupted in Deraa on March 18, with pro-democracy protests spreading to regions across the rest of Syria.
Three days later the Fourth Mechanised Division, under the control of Assad brother's Maher stormed Deraa, echoing their his father's 1982 attack on the city of Hama to crush a revolt led by the Muslim Brotherhood, killing anywhere between 10,000 and 30,000 people.
Assad tightened the security grip in and around Damascus on Thursday, with various security forces and secret police units deploying in the nearby towns, Erbin and Tel and in the Damascus district of Barzeh and the suburbs of Douma and Daraya, rights activists and witnesses said.
The Syrian Observatory for Human Rights said the attack on Deraa has killed at least 50 civilians, with essential supplies in the city running law.
The offensive helped intensify criticism against Assad in the West, which took steps to rehabilitate the Syrian ruler in the last three years. The United States says it is considering tightening sanctions.
Ambassadors of European Union governments to Brussels plan to meet Friday to discuss the possibility of imposing sanctions against Syria, which could include asset freezes and travel restrictions on key officials.
One EU diplomat said it may be too early for the bloc to make a binding decision Friday but governments could send a message signaling sanctions were on the table.
"I'd expect a political signal toward sanctions but maybe not a decision yet," the diplomat said.
Other EU measures against Syria could include freezing financial aid, which amounts to 43 million euros ($64 million) a year.

(Editing by Jon Hemming)