U.S. Ambassador to the United Nations Susan Rice said on Saturday she was "disgusted" by the Russian and Chinese veto on a Security Council resolution on Syria that urges President Bashar al-Assad to step down.

Thirteen of the council’s 15 members voted in favor of the resolution aimed to stop the ongoing violence in Syria.

"Any further bloodshed that flows will be on their [Russia's and China's] hands," she said.

U.S. Secretary of State Hillary Clinton said the failure to condemn President al-Assad increased the risk of more bloodshed and civil war in Syria.

"If we do not begin the process, I know what will happen: more bloodshed, increasing resistance by those whose families are being killed and whose homes are being bombed, and a greater likelihood that Syria will descend into civil war," she said.

Russian Ambassador Vitaly Churkin said the draft resolution “did not reflect Syria’s realities well enough and sent conflicting signals to the political forces in Syria.”

Russian Foreign Minister Sergei Lavrov previously said the resolution did not set enough demands on anti-government armed groups, and that Russia was concerned it could jeopardize the national dialogue among political forces in Syria.

Lavrov said earlier on Saturday he and Foreign Intelligence Service head Mikhail Fradkov will visit Syria and meet with President al-Assad on February 7. The visit will be made on instructions from Russian President Dmitry Medvedev. Lavrov did not reveal any details of the upcoming the visit.

This is the second time that Russia and China as permanent members have vetoed the Syria issue. In October, they blocked a European-sponsored resolution condemning Syria and threatening possible sanctions.

At least 5,400 people have been killed in the Syrian government's 11-month crackdown on protesters, according to the UN. Syrian authorities blame the violence on armed gangs affiliated with al-Qaeda and say more than 2,000 soldiers and police have been killed.

The West has been trying to persuade Moscow to support a resolution effectively authorizing a military operation but Russia has repeatedly insisted that the Western drive for a stronger crackdown on Syria is preparation for a “Libyan scenario.”

Russia, one of President al-Assad’s firm supporters during the uprising against his regime, indicated earlier this week that it would veto the draft resolution calling on Assad to step down. Moscow has proposed its own draft, which the West criticized as being too soft.