The United States placed 12 Russians on a blacklist Tuesday for ties to the 2009 death of human rights lawyer Sergei Magnitsky and to murders of two others who exposed official corruption.

Ten of the 12 were officials at prisons where Magnitsky was detained, law enforcement and judiciary officials, and participants in the massive tax fraud that Magnitsky exposed and was killed over.

The U.S. Navy is sending a guided missile cruiser to the Black Sea, the Pentagon said Tuesday, the latest bid by Washington to to reassure allies worried over Russia's intervention in Ukraine.

"I can confirm the Vella Gulf, a Navy cruiser, will be going in to the Black Sea probably later this week," Pentagon spokesman Rear Admiral John Kirby told reporters.

Russia would veto a draft United Nations Security Council calling for Syria to be hauled before the International Criminal Court, deputy foreign minister Gennady Gatilov said Tuesday.

"The draft resolution that is currently submitted to the Security Council for us is unacceptable and we will not support it. If it is put to a vote, we will veto it," Gatilov told the Interfax news agency.

Russia and Western powers are on the brink of a new Cold War over the crisis in Ukraine, Russian Prime Minister Dmitry Medvedev said in an interview broadcast Tuesday.

"Basically we are slowly but surely approaching a second Cold War that nobody needs," Medvedev said in an interview with Bloomberg Television that was also published on the Russian government's website.

China and Russia started joint naval exercises off Shanghai on Tuesday as their leaders promised to strengthen relations in the face of international criticism over their territorial disputes.

President Xi Jinping launched the drills at a ceremony in a room lined with officers of both navies in white dress uniform, with his Russian counterpart Vladimir Putin looking on, state broadcaster CCTV showed.

Ukraine said Tuesday that Russian troops had moved away from the border, just five days before the country's make-or-break presidential poll, but stopped short of confirming a full withdrawal as demanded by the West.

Moscow had announced it was pulling back its forces in a move that has the potential to deflate a bloody Kremlin-backed insurgency threatening to tear the ex-Soviet nation apart.

Russian troops ordered by President Vladimir Putin to return to their bases from near the Ukrainian border were preparing their departure on Tuesday, the defense ministry said.

"The commanders in the exercise areas are now clarifying the routes and movement plans" for the troops to leave, Interfax quoted a ministry source as saying.

Held up by many as the best hope for Ukraine, Sunday's presidential vote will make little difference to the one man the West blames most for the country's crisis -- Vladimir Putin.

Bent on countering Western ambitions in Ukraine, Russia's leader will never accept a vote that cements the authority of Kiev's new government, analysts say.

Russia said Monday it had ordered troops near the border with Ukraine to return to their bases, just days ahead of a presidential vote aimed at bringing the country out of deep crisis.

The move could ease tensions, but both Washington and NATO -- which noted it was the third time Moscow had made such a claim -- said they saw no sign of a withdrawal.

With a bloody insurgency raging in the east, the ominous presence of Russian troops across the border and an economy in deep recession, next Sunday's election will determine the very survival of Ukraine.

But it is unclear whether a large chunk of the population will want to -- or be able to -- turn out to choose a new president for a country many fear is on the brink of civil war.