Crude futures hit 3-week lows on Monday as Greece shut its banks and imposed capital controls, causing widespread risk aversion, while Iran looked likely to extend nuclear negotiations with the West to export more of its oil into an oversupplied market. Also, the Iran deadline for a nuclear pact could be pushed out by a week or so from tomorrow, so it’s a risk-off day,” said Tariq Zahir, an oil bear at Tyche Capital Advisors in Laurel Hollow, New York.