Syrian protesters appealed Friday to the many Syrians who have not yet turned against the government to join them in an escalated push for the ouster of President Bashar al-Assad during the holy Muslim month of Ramadan, which will start in the coming days.

Hundreds of thousands of Syrians took to the streets for what has become a weekly ritual of protests after Friday prayers since the uprising began in March. This week, activists dubbed the day “Your silence is killing us,” a reference to the inaction of both the international community and the millions of Syrians they suspect do not back their government but have refrained from joining the protests.

Activists are hoping that Ramadan, during which Muslims fast from dawn to dusk then attend evening prayers after they have eaten, will galvanize the protests by bringing people together in mosques every night and creating fresh opportunities for demonstrations.

The focus of the effort is Damascus, where a growing number of neighborhoods have joined in protests in recent weeks in a sign that the government can no longer count on the capital’s loyalty.

An appeal has been launched on Facebook to mark the first day of Ramadan by occupying Umayad Square in the heart of the city, which would also mark a first for the Syrian uprising. Although there have been massive protests in some cities, Damascus has yet to witness the kind of large-scale gathering that might directly threaten the Assad regime.

A clampdown in the capital in recent days appeared designed to head off potential Ramadan unrest, with more than 1,000 people detained there, 300 of them on Friday alone, according to Rami Abdelrahman of the London-based Syrian Observatory for Human Rights. Witnesses said checkpoints were erected across the city to keep people from protests, mosques that have witnessed protests in the past were forced to close, and several neighborhoods that had emerged as flash points of unrest were sealed off.

More than 150 people were detained in one incident in Midan, the only Damascus neighborhood where protests have regularly taken place since the uprising began, said an activist who attended the protest and uses the nickname Alexander Page to avoid detection. Three people were injured when security forces opened fire, aiming for their legs but not to kill, he said.

Fifteen people were killed nationwide by security forces, according to the Local Coordination Committees, a group that organizes and monitors protests. The death toll was lower than on most previous Fridays, perhaps a sign that the security forces have realized the riskiness of killing people on the eve of Ramadan.

Activists say they hope the religious sensitivity of the holy month will deter the government from shooting protesters and will encourage more people to believe it is safe to take to the streets. Deaths in Ramadan would “anger Muslims and provoke some kind of sectarian war,” said Page, interviewed over Skype from Damascus.

Some fear that is the intent of a regime dominated by members of the Alawite minority to which Assad belongs. Others fear that the uprising will be hijacked by religious extremists within the Sunni majority, which has dominated the protests but has also repeatedly asserted its commitment to nonviolent resistance.

Meanwhile, the official Syrian news agency SANA blamed an explosion that damaged an oil pipeline near the western town of Tal Kalakh on “saboteurs” and implied that members of the protest movement were behind it. The bombing “proves that the saboteur groups are linked with foreign plots,” the agency quoted Irrigation Minister George Soumi as saying.

Reports from the eastern town of Deir el-Zour of battles overnight Thursday between defected army soldiers and other branches of the security forces added to the pre-Ramadan tensions. Four people were reported killed overnight, apparently by security forces who tried to enter the town, a staunch center of opposition that has been effectively controlled by protesters for several weeks. But human rights activists who contacted residents of the town said the defections did not appear to be large-scale.