Britain, France, Spain and the United States had sought the measures to shore up efforts by U.N. envoy Bernardino Leon to clinch a political deal before the start of Ramadan on June 17.

The four countries asked that a global travel ban and an assets freeze be imposed on Abdul Rahman Swehli, a politician from Misrata, and Othman Maliqta, commander of the Zintani Qaqa brigade.

A new crucial round of talks is opening in Rabat on Monday.

The U.N. sanctions committee had given the 15 members of the Security Council until 1900 GMT to raise objections.

Russia and China spoke out and said they would not back the proposed sanctions, diplomats said.

The two Libyans are not considered high-profile, but the decision to target them first was aimed at sending a message to more senior-ranking officials that they must get onboard.

Libyan factions agreed during Geneva talks in January to set up a national unity government to restore stability that has been shattered since the 2011 fall of Muammar Qaddafi.

But months of U.N.-brokered negotiations have yet to produce a political accord.