Syria violence outrageous: Obama

United States President Barack Obama has condemned Syria's "outrageous" use of violence against anti-government demonstrators, accusing the regime of seeking Iran's aid to quell the rebellion.

"Instead of listening to their own people, President Bashar al-Assad is blaming outsiders while seeking Iranian assistance in repressing Syria's citizens through the same brutal tactics that have been used by his Iranian allies," Obama said in a statement.

Obama said the US continues to oppose Syrian government's destabilising behaviour, including support for terrorism and terrorist groups. "This outrageous use of violence to quell protests must come to an end now. We regret the loss of life and our thoughts are with the families and loved ones of the victims, and with the Syrian people in this challenging time.

"The Syrian government's moves on Friday to repeal Syria's decades-old Emergency Law and allow for peaceful demonstrations were not serious given the continued violent repression against protesters," he said.

Obama said over the course of two months since protests in Syria began, America has repeatedly encouraged al-Assad and the Syrian government to implement meaningful reforms, but they "refuse to respect the rights of the Syrian people or be responsive to their aspirations."

"The Syrian people have called for the freedoms that all individuals around the world should enjoy: freedom of expression, association, peaceful assembly, and the ability to freely choose their leaders. President Assad and the Syrian authorities have repeatedly rejected their calls and chosen the path of repression," he said.

The US president said the Syrian regime had placed their personal interests "ahead of the interests of the Syrian people", resorting to the use of force and "outrageous human rights abuses" to compound the already-oppressive security measures in place before the demonstrations erupted.

Obama's comments came after activists and rights groups said Syrian government forces killed at least 72 people when they opened fire on demonstrators, seeking to disperse thousands who took to the streets for Good Friday protests.