Syrian forces killed at least six people on Saturday when they fired on mourners calling for the end of President Bashar Al-Assad's rule at mass funerals of pro-democracy protesters shot a day earlier.

Witnesses and rights campaigners said security forces killed three people in Damascus's Barzah district and a further three when they fired at mourners trying to join funerals near Izra'a in southern Syria, where at least 12 burials were taking place.

The mourners were chanting "Bashar Al-Assad, you traitor! Long live Syria, down with Bashar!"

"There was a heavy volley of gunfire in our direction as we approached Izra'a to join the funerals of martyrs," a witness from the southern city of Deraa who came to join the burials told Reuters.

Security forces also opened fire at a funeral in Damascus's Douma suburb, wounding three people, witnesses there said.

Mourners in Harasta, a town near Damascus, also came under fire from security forces, before staging a sit-in to demand the release of detainees arrested in the last few weeks.

Protesters staged another sit-in after a funeral for four people from Irbeen, near Damascus. "We are not leaving until the political prisoners are released," one protester told Reuters by phone.

Friday was by far the bloodiest day in over a month of demonstrations to demand political freedoms and an end to corruption, with at least 100 people killed, said two activists.

Friday's violence, in areas stretching from the port city of Latakia to Homs, Hama, Damascus and the southern village of Izra'a, brings the death toll to more than 300, according to activists, since unrest broke out on March 18 in Deraa.

Damascus remained tense on Saturday and many people stayed indoors, one activist told Reuters from the capital.

"This is becoming like a snowball and getting bigger and bigger every week. Anger is rising, the street is boiling," he said.

Two Syrian lawmakers, both from Deraa, told al-Jazeera television they were resigning from parliament in protest at the killing of demonstrators. Theirs were the first resignations from within Assad's autocratic regime.

"Security solutions do not work," said one of the lawmakers, Khalil al-Rifaei.

Syrian parliament is effectively appointed by the authorities. Resignations were unheard of before the protests.

Crackdown condemned

US President Barack Obama condemned Friday's violence and accused Assad of seeking help from Iran. A Syrian government source said in a statement published on official state media Obama's statement "was not based on objective vision."

"This outrageous use of violence to quell protests must come to an end now," Obama said in a statement. "Instead of listening to their own people, President Assad is blaming outsiders while seeking Iranian assistance in repressing Syria's citizens." France's Foreign Ministry said Paris was "deeply concerned".

"Syrian authorities must give up the use of violence against their citizens. We again call on them to commit without delay to an inclusive political dialogue and to achieve the reforms legitimately demanded by the Syrian people," it said.

Friday's protests went ahead despite Assad's decision this week to lift the country's hated emergency law, in place since his Baath Party seized power 48 years ago.

A statement by the Local Coordination Committees, a grouping of activists coordinating protests, said the end of emergency law was futile without the release of thousands of political prisoners -- most held without trial -- and the dismantling of the security apparatus.

In their first joint statement since the protests erupted last month, activists said the abolition of the Baath Party's monopoly on power and the establishment of a democratic political system was central to ending repression in Syria.

Aided by his family and a pervasive security apparatus, Assad, 45, has absolute power, having ignored demands to transform the anachronistic autocratic system he inherited when he succeeded his late father, president Hafez al-Assad, in 2000.

Amnesty International said Syrian authorities "have again responded to peaceful calls for change with bullets and batons".

"They must immediately halt their attacks on peaceful protesters and instead allow Syrians to gather freely as international law demands," said Malcolm Smart, Amnesty International's Middle East and North Africa director. – Reuters