[TOKYO] Oil prices fell in early Asian trade after a strong two-day rally that was fed by easing concerns Britain would leave the European Union after a referendum this week, allowing market participants to focus on supply issues.
Saudi Arabia's crude oil exports also dropped despite high production levels, suggesting demand remains in a deficit to supply.
US crude's expiring July front-month contract was down 18 US cents at US$49.19 a barrel at 0046 GMT. The more actively traded August contract, the new front-month from Wednesday, was down 19 US cents at US$49.77. That contract settled up nearly 3 per cent at US$49.96 on Monday.
Brent crude futures' August front-month contract was down 31 US cents at US$50.34 a barrel.
On Monday it rose US$1.48, or 3 per cent, to US$50.65 a barrel. The contract has risen about 7 per cent since Thursday's settlement, after falling 10 per cent in six previous sessions.
Saudi Arabia's crude exports in April fell to 7.444 million barrels per day from 7.541 million bpd in March, official data showed on Monday.
The world's largest oil exporter and Opec heavyweight produced 10.262 million bpd in April, compared with 10.224 million bpd a month earlier, the data showed.
Potentially adding to supply, Iran has increased its crude exports capacity at its main terminal on Kharg Island to allow eight tankers to load simultaneously, the oil ministry's news agency Shana reported on Monday.
Following upgrades to infrastructure over the past two years eight tankers can berth at the terminal's eastern harbour, with one more vessel able to load ship-to-ship cargo at the same time.