(CNN) -- Violence swept across Syria on Friday, with at least 43 people reported killed in another bloody day of confrontation between government forces and demonstrators calling for political change.
Reliable numbers were difficult to come by. CNN bases its figures on reports from witnesses. Amnesty International, citing local human rights activists, reported that at least 75 people were killed in Friday's protests. The Syrian government does not permit CNN to report from inside the country.
The killings occurred in several flashpoint regions as thousands of Syrian protesters defiantly marched after Muslims' weekly prayers in a display of mass discontent toward the government.
Violence ripped through the Damascus suburbs of Douma, Moademy, and Zamalka, and other cities -- Homs, Harasta, and Izraa. The state-run news agency reported demonstrations and clashes, citing injuries but no deaths.
Human rights groups and witnesses told a different story. "Today, they have killed so many people. There are so many people injured and people have been kidnapped," Wissam Tarif, a human rights activist, told CNN. "They are acting as an armed gang, not as security forces."
The violence prompted international condemnation, with British Foreign Secretary William Hague calling the killings "unacceptable," and calling on Syrian security forces "to exercise restraint instead of repression, and on the Syrian authorities to respect the Syrian people's right to peaceful protest."
Before Friday's marches, Amnesty International and Human Rights Watch said the death toll had exceeded 200 since the demonstrations began in mid-March.
Human rights groups had been urging the government to refrain from cracking down on peaceful turnouts during the Facebook-inspired outpouring dubbed "Great Friday."
A witness in Douma said eight people died and approximately 25 were wounded when security forces fired on several thousand protesters. Riot police and secret police comprised the security forces and a sniper on a hospital roof was seen taking shots at people. Pellets and lethal rounds were used, the witness said, as people chanted for the downfall of the regime.
A doctor in the Damascus suburb of Moadamy said six people were killed and dozens wounded when security forces fired in an "indiscriminate and disproportionate manner" on thousands of demonstrators. The doctor, a pediatrician, said it was difficult taking the wounded to the hospital. Syrian security forces had set up checkpoints across the area and were preventing anyone from entering or leaving the suburb.
Five people were killed in the Damascus suburb of Zamalka, a witness said.
An opposition leader in Homs said 12 people died and dozens were wounded when security forces fired on demonstrators. Protesters raced from the main streets for cover in smaller streets and alleys where they waited for the situation to calm. A witness said one of the dead was a 41-year-old demonstrator who was shot in the neck.
Tarif said security forces fired on demonstrators from the southern city of Izraa who were trying to join protesters in nearby Daraa, killing nine and wounding others. Two people in Izraa reported seeing an assault on demonstrators and many casualties.