Brent crude has fallen to another 12-year low due to Iranian oil supplies looming on the market.
The global benchmark edged down as far as $29.73 and down more than 1.5%, while the US West Texas Intermediate (WTI) increased 43 cents at $30.91, Reuters reported.
The news agency reported Barclays saying that Iran’s return is expected soon.
Barclays said: "Non-OPEC supply ex-US is lower, though the adjustments are not nearly steep enough to rebalance given the worsening demand outlook and higher OPEC supply."
The United Nations’ nuclear watchdog International Atomic Energy Agency (IAEA) is expected to confirm that Iran has restricted its nuclear programme as agreed with world powers, which may lead to the lifting of sanctions.
According to a diplomatic source, the report is set to be released on Friday.

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By GlobalDataOn Wednesday, the Iranian Revolutionary Guard released ten US sailors to the American naval fleet in the Persian Gulf after holding them overnight.
The sailors were freed as after authorities learnt that the entry of their vessels into the country’s waters was not intentional.
According to a report from Wood Mackenzie, projects worth $380bn have been postponed or cancelled since 2014, after oil and gas companies reduced costs in order to survive the oil price crash.
The report also revealed that projects worth $170bn have been planned between 2016 and 2020.