The four European members of the Security Council -- Britain, France, Germany and Portugal -- said Thursday that they would begin working on a Security Council sanctions resolution on Syria.

"We believe that the time has come for the council to take further actions to step up the pressure against those who are responsible for the violence against the citizens of Syria," said Philip Parham, British deputy permanent representative to the UN.

"So we will be working on a Security Council resolution which will include measures to apply that pressure to those that are responsible and we will be discussing that resolution with our colleagues on the council over the coming days," he told reporters outside of the Security Council chamber.

The German, French and Portuguese envoys echoed his remarks.

The United States would support further action in the Security Council through a resolution, U.S. deputy permanent representative Rosemary DiCarlo said.

Syria has been in unrest since mid March when anti-government protests broke out in the southern province of Daraa and spread to other cities.

The Syrian authorities blamed the unrest on "armed groups and foreign conspiracy" and stressed that it would track down gunmen who have intimidated people and damaged public and private properties.

Russia and China, as permanent members of the 15-member council who have the right to veto, opposed tough measures against Syria. Brazil, India and South Africa, non-permanent member of the council, also went against sanctions on Syria.