US West Texas Intermediate crude futures were down 16 cents, or 0.4 per cent, at $46.19 a barrel
With the shale oil revolution and the end of the petrodollar, the US is set to hit its enemies where it hurts the most - in their pockets
Brent crude settled down 66 cents, or 1.3 per cent, at $49.26 a barrel
Futures climbed 0.7 per cent Friday, trimming a weekly loss
Experts said that the market is jittery due to uncertainty over the outcome of next month's OPEC meet
US West Texas Intermediate crude was down 40 cents, or 0.84 per cent, at $47.01 per barrel
Brent crude futures were trading at $49.93 per barrel at 0641 GMT, down 95 cents, or 1.87 percent
Brent crude futures were trading at $50.22 per barrel at 0224 GMT, down 66 cents, or 1.3 per cent
Investors are wondering whether Saudi Arabia will be amenable to a freeze if Iran doesn't participate
Traders said the price falls were the result of cashing in following more than two weeks of rallying prices
The kingdom is also engaged in a battle for market share with rival Iran and has cut prices to its customers in Asia, the biggest market for both exporters
Refiners have resorted to production cut which will weaken demand for crude oil and serve as a hard ceiling on prices
Since the plunge in oil prices that began in mid-2014, Venezuela has repeatedly tried to broker deals to freeze production and reduce a supply glut, with limited success
Finance Minister had jitters when crude prices came close to $53 a barrel in June rallying from 12-year lows of $27 earlier in the year
Brent futures were up 15 cents at $44.42 per barrel on Monday
For the first seven months of 2016, India imported about 359,000 bpd of Iranian oil, up 67 per cent from the same period a year ago
On the back of bargain-buyers taking advantage of a weaker dollar
Overproduction of crude and a wave of refined products were the main factors weighing on oil
Oil recovery proves slippery for Exxon and Chevron
Brent crude is still up more than 60% from a 12-year low near $27 in January