China and Russia have vetoed a resolution by the U.N. Security Council calling for the resignation of Syrian President Bashar al-Assad amid worsening violence in that country.

The resolution backed a similar resolution proposed earlier by the Arab League.

All other 13 members of the Security Council, including the UK, France and the United States, voted in favor of the resolution.

Russia had earlier learned it would not support a draft of the resolution that envisioned Assad’s ouster because it did not specify enough demands on the anti-government movement in Syria.

It is a sad. day for this council, a sad, day for Syrians, and a sad, day for all friends of democracy, said French Ambassador Gerard Araud after the rare double-veto.

Araud added that he thinks China and Russia are now “complicit” in the atrocities being committed by Assad’s soldiers.

Today the Security Council has failed to live up to its responsibility, German Ambassador Peter Wittig said.

The people in Syria have been let down again.

Mohammed Loulichki, Morocco's ambassador to the UN and the only Arab member of the current council, expressed his great regret and disappointment that Moscow and Beijing rejected the resolution.

Susan Rice, the U.S. ambassador, said she was disgusted by the vetoes.

France’s foreign minister, Alain Juppe, vigorously supports the resolution against Assad, citing that the hardening violence in Syria underlines the urgency that the U.N. Security Council must break its silence to denounce the authors of this crime. The international community must recognize and support the right of the Syrian people to freedom, to security and to the choice of its political future. Those who block the adoption of such a resolution are taking a grave historical responsibility.

Prior to the vote, U.S. President Barack Obama expressed his strong support of the resolution

The international community must work to protect the Syrian people from this abhorrent brutality, Obama said in a statement.

The Syrian regime's policy of maintaining power by terrorizing its people only indicates its inherent weakness and inevitable collapse. Assad has no right to lead Syria, and has lost all legitimacy with his people and the international community.

Syria and Russia are long-time allies; Russia has extensive infrastructure investments in the country. Russia and China also opposed a similar move to condemn Syria last October, citing that they would not accept a forcible regime change in Damascus, nor the possibility of foreign military intervention there.

According to Russian news agencies, Russia’s Foreign Minister Sergey Lavrov and Russia's foreign intelligence chief, Mikhail Fradkov, are expected to meet with Assad in Damascus on Tuesday.

Separately, Tunisia has moved to cut off relations with Assad’s regime.

Meanwhile, Syrian security forces are believed to have killed 55 people in the city of Homs, in one of the bloodiest incidents since the revolt erupted last year. According to Syrian human rights activists, Syrian forces used mortars and artillery against civilians.

Obama described the latest killings as an “unspeakable assault.”

At least 5,400 people have been killed in Syria as a result of Assad’s brutal crackdown on the demonstrators.