Foreign Secretary William Hague has called on Syria's president Bashar Assad to allow a peaceful political transition in his country, following an overwhelming vote in the United Nations condemning human rights violations by his regime.

Some 137 countries backed a non-binding resolution at the UN General Assembly in New York supporting an Arab League plan that calls for Assad to step down and prepare the way for a new government in the Middle Eastern state.

Just 12 nations voted against the motion, but they included permanent UN Security Council members Russia and China, who have blocked proposals for a binding resolution in the 15-member council.

Mr Hague said the vote sent an "unambiguous" message to Damascus that the violence against protesters who have challenged the Assad regime must stop immediately. He called on UN secretary general Ban Ki-moon to appoint a special representative to work alongside the new Friends of Syria group, which meets for the first time in Tunisia on February 24.

"Members of the UN voted overwhelmingly to back the Arab League's plan for a Syrian-led solution to the crisis," said Mr Hague.

"The resolution, which explicitly endorsed the Arab League plan of November 2 as well as its decisions on January 22 and February 12, was co-sponsored by 72 countries and supported by 137 members of the Assembly. It sent a clear signal of the international community's condemnation of the Syrian regime's actions and intention to hold to account those responsible for the ongoing atrocities.

"The message is unambiguous. The violence must stop immediately."

Mr Hague added: "I look forward to discussing how we can support the Arab League further at the Friends of Syria meeting next week. I hope that the UN secretary general will swiftly appoint a special representative to work alongside them.

"President Assad and the Syrian regime must heed the call of the international community and allow a peaceful political transition to resolve the crisis. President Assad and those around him should be under no doubt that we will continue to support the Syrian people in their aspiration for a peaceful political transition in Syria."