An independent inquiry must be held into the recent killings of Syrian protesters by security forces, rights activists say.
US-based Human Rights Watch led the call for an inquiry after 94 people were reported killed since Friday.
The group urged international sanctions against those ordering the shootings.
Reports from Syria say security forces have continued to round up dissidents, despite the government lifting a long-running state of emergency last week.
"After Friday's carnage, it is no longer enough to condemn the violence," Joe Stork of Human Rights Watch said in a statement.
"Faced with the Syrian authorities' 'shoot-to-kill' strategy, the international community needs to impose sanctions on those ordering the shooting of protesters."
Other groups, including UK-based Syrian Observatory for Human Rights and Swiss-based International Commission of Jurists, also urged international investigations of the killings.
Western governments have repeatedly condemned the violence, and on Sunday the UK advised its citizens to leave Syria because of the deteriorating security situation.
Calls to quit
Protests began five weeks ago, with small crowds inspired by events elsewhere in the region gathering to demand modest reforms.
The authorities have reacted erratically - sometimes promising to allow more democracy and freedoms, and other times opening fire on demonstrators.
Witnesses say the protesters' goals have become much more radical, with many now demanding President Bashar al-Assad step down.
The past two days have been the bloodiest since the protests began.
Activists say at least 82 people were killed during protests on Friday, and 12 people were shot and killed the next day as they attended funerals for those protesters.
Security forces opened fire on mourners gathering in parts of the capital Damascus and near the flash-point southern town of Deraa, according to witnesses.
The violence came after President Assad scrapped the decades-old state of emergency - one of the main demands of the protesters.
