By Michelle Nichols

UNITED NATIONS Oct 9 (Reuters) - The United Nations Security Council on Friday voted to amend the mandate of a peacekeeping mission in South Sudan so it can back implementation of a recent peace deal, but Russia and Venezuela abstained over concerns about sanctions and surveillance drones.

A political row between South Sudan's President Salva Kiir and his former deputy Riek Machar sparked civil war in late 2013 and reopened ethnic fault lines between Kiir's Dinka and Machar's Nuer people. More than 10,000 people have been killed.

Kiir and Machar signed a peace deal in August, but since then both sides have accused one another of attacks, and humanitarian groups have pulled out of parts of the oil-rich country where heavy violence has been reported.

Some 13,000 U.N. peacekeepers are still sheltering more than 200,000 people at camps throughout South Sudan. Peacekeepers have been deployed in South Sudan since the country declared independence from Sudan in 2011.

"This resolution expresses our continued commitment to maintain pressure on both sides, neither of which has fully complied with its ceasefire obligations," U.S. deputy U.N. Ambassador David Pressman told the council.

The U.S.-drafted Security Council resolution extended the peacekeeping mission until Dec. 15. It warns of targeted sanctions against people who threaten South Sudan's peace, security and stability, using the same language contained in a resolution adopted by the council in May to renew the operation.

"The South Sudanese parties now need support and encouraging efforts to implement the agreement and settling the conflict in South Sudan, whereas the threat and use of sanctions can only harden their positions," Russia's deputy U.N. Ambassador Petr Iliichev told the council after the vote.

Venezuela said a threat of sanctions was counterproductive, while China, which voted in favor of the resolution, said the council should be cautious when considering imposing sanctions.

Russia, Angola and Venezuela last month objected to a U.S. bid to impose U.N. sanctions on South Sudan's army chief and a rebel commander for their roles in the conflict.

Russia's Iliichev also said Moscow advised against asking U.N. Secretary-General Ban Ki-moon to deploy surveillance drones as part of the peacekeeping mission because the South Sudanese government had objected to such a move.

South Sudan's U.N. Ambassador Francis Deng said the call for surveillance drones "without consultation with the government is to invite controversy, and potential disagreement and hostility, when harmony and cooperation are what the situation calls for." (Reporting by Michelle Nichols; Editing by Lisa Shumaker)