Brent oil drops to $28 per barrel as Iran increases production and exports after international sanctions against the country were lifted.
Brent oil prices fell on Wednesday, dropping below $30 a barrel to touch $29.96 for the first time since April 2, 2004.
Euro zone government borrowing costs slid to new lows on Thursday, a day after the European Central Bank pledged to fulfill its 1 trillion euro bond-buying program, although regional stocks took a step back from this week's multi-year peaks.
Oil settled down for a second straight session on Monday as Iran and six world powers tried to negotiate a deal on Tehran's nuclear program that could end Western sanctions and allow the OPEC member to ship more crude into an already flooded market.
Oil tumbled 5 percent on Friday, erasing the previous session's gains, as Yemen's conflict looked less likely to disrupt Middle East crude shipments and investors turned their focus to talks for a potential Iran nuclear deal that could put more supply on the market.
Oil settled up about 3 percent on Wednesday as a weak dollar, fighting in Yemen and speculative buying boosted crude prices in spite of U.S. inventories building to record highs for an 11th week.
Oil jumped for a third straight session on Monday as OPEC forecast greater demand for crude this year than previously thought and projected less supply from countries outside the producer group.
Oil prices crashed on Wednesday, with U.S. crude losing 9 percent in one of its biggest daily routs ever, as record high oil inventories in the United States cut short a four-day rally.
Oil prices fell more than 1 percent on Wednesday after touching their lowest in nearly six years the previous session, extending losses alongside a sell-off in other commodities.
Brent oil extended losses into a fourth session on Tuesday, with prices hovering close to a more than five-year low above $57 per barrel, as persistent worries about a global supply glut offset concerns about output disruptions in Libyan.
An uneasy calm settled on Asian markets on Wednesday as a brewing financial crisis in Russia and the rout in oil prices sent investors scurrying for the cover of top-rated bonds.
Saudi Arabia blocked calls on Thursday from poorer members of the OPEC oil exporter group for production cuts to arrest a slide in global prices, sending benchmark crude plunging to a fresh four-year low.
Asian shares bounced back and the dollar fell on Thursday after minutes of the U.S. Federal Reserve's latest policy meeting showed policymakers have some concerns about downside risks to the global economy and the dollar's strength.
A second day of weak German data sent European markets into retreat on Tuesday with stocks, the euro and periphery euro zone government debt all knocked by the mounting evidence of an abrupt slowdown in the bloc's economic engine room.