Oil fell as weak demand in Europe and Asia and ample supply in the Atlantic basin outweighed political drama in Ukraine and the Middle East.
Fears over Ukraine unrest and an upcoming slew of US data are also pushing some currencies slightly down against the dollar.
Oil prices fell on Tuesday, with U.S. crude leading the decline as a refinery fire in Kansas curbed demand for the benchmark.
Asian stocks rose for a second session on Tuesday on hopes that growth in the world's second-largest economy has finally stabilized.
U.S. stock-index futures rose Tuesday as investors looked to economic reports, earnings and the Fed's mid-week policy decision.
Stocks were little changed on Monday amid activity on the corporate-deal front.
The Treasury Department auctioned $29 billion of 2-year notes at a high yield of 0.54 percent, the highest yield since May 2011.
European shares closed lower on Monday, with investors focused on corporate earnings as well as developments in Ukraine and Gaza.
Gold rebounding from a one-month low, as heightened tensions over Ukraine prompted speculators to buy back bullion.
Gold held above $1,300 an ounce as heightened tensions with Russia, and violence in the Middle East, boosted its safe-haven appeal.
Asian equities were mostly higher on Monday, led by a rally in Chinese markets, on optimism about the health of the world's second-largest economy.
U.S. stocks finished lower on Friday weighed by Amazon's weak earnings and Visa's lowered outlook, in addition to ongoing geopolitical concerns.
U.S. Treasury debt prices jumped on Friday ahead of a Federal Reserve policymakers' meeting next week.
U.S. stock-index futures declined early on Monday, as investors continued to monitor geopolitical risks.
European shares ended the day lower, as concerns about the impact of further sanctions against Russia weighed amid ongoing unrest in Ukraine.
Oil fell on Thursday, as unseasonably weak demand and plentiful supplies of crude and refined products offset strong Chinese factory data.
Brent crude oil rose above $108 a barrel, as fighting in Ukraine and chilly relations between Russia and the U.S. ignited new supply fears.
The euro climbed from an eight-month low on Thursday after German and French business activity beat expectations.
The dollar fell slightly against the euro ahead of Wednesday's release of US gross domestic product growth and a Fed policy announcement.
The euro struggled to hold above eight-month lows against the dollar on Friday, hurt by a dive in Germany's Ifo survey of business sentiment.
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India's economic growth slowed to 7 percent in the three months through June from 7.5 percent in the previous quarter, data showed on Monday.
Euro zone annual inflation came in at 0.2 percent in August on Monday, marking a stable reading for the second month in a row.