OREANDA-NEWS. Crude futures plunged today as Greek voters' rejection of a debt bailout threatened to worsen the already weak economic outlook of the European Union just as Iran and world powers head closer to a nuclear deal.

The Nymex light, sweet futures contract settled lower by $4.40/bl to $52.53/bl, its weakest since 13 April when it ended at $51.91. Ice Brent settled down by $5.53/bl to $56.54/bl, its largest single day decline since 27 November and first time closing below $60/bl since 14 April. The Brent-WTI spread narrowed by $1.13/bl to $4.01/bl.

The Greek public, through a referendum, voted against a bailout offered by lenders that sought more austerity measures. While Greece is not a major consumer of oil, the rejection has raised the possibility of Athens exiting the economic bloc. That uncertainty saw forex investors sell the euro in favor of the dollar, further boosting the already strong currency. A strong dollar weighs on commodities such as oil that are priced in it.

The fall in WTI below its 100-day moving average, and its subsequent break below a support of $56.50/bl "adds to our bearish conviction," UK-bank Barclays said in a technical analysis of the benchmark. "We are looking for a move lower towards targets in the $49.90-$50.45" range.

Prices were also under pressure by turbulence in China's stock markets. After a week of falling equity prices, Beijing has suspended initial public offerings, and fund managers and brokerages have pledged to buy back shares. Volatility in Chinese equity markets can have a ripple effect on oil as China is the world's second-largest oil consumer.

Investors are also monitoring Iran's nuclear talks. With the deadline tomorrow, an agreement and the lifting of trade sanctions may allow the key Middle Eastern producer to step up oil exports to an already well-supplied market facing a weak demand outlook.

Nymex RBOB dropped by 11.06?/USG to $1.9237/USG. Nymex ultra-low sulfur diesel (ULSD) settled lower by 13.10?/USG to $1.7089/USG.