By Christopher Johnson

Brent crude oil was down 30 cents a barrel at $72.53 by 0815 GMT. U.S. light crude was 30 cents lower at $62.84 a barrel.

Both oil price benchmarks have lost more than 15 percent since hitting four-year highs in early October, as hedge funds have cut bullish bets on crude to a one-year low, data show.

Washington imposed sanctions against Iran on Monday, restoring measures lifted under a 2015 nuclear deal negotiated by the administration of former U.S. president Barack Obama, and adding 300 new designations including Iran's oil, shipping, insurance and banking sectors.

In response, Iranian President Hassan Rouhani said in speech broadcast on state TV that Iran would break the sanctions and continue to sell oil.

Washington has granted some exemptions. The United States said on Friday it will temporarily allow eight importers to keep buying Iranian oil.

"The impact of the sanctions is going to be largely softened as a result of this allowance," said Surfeit Vijayakar, director of energy consultancy Trisect.

Washington has so far not identified the eight. China, India, South Korea, Turkey, Italy, the United Arab Emirates and Japan have been the top importers of Iran's oil, while Taiwan also occasionally buys Iranian crude.

South Korea said on Monday it had been granted a waiver, at least temporarily, to import condensate, a super-light form of crude oil, from Iran. It was also allowed the continue financial transactions with the Middle East country, it said.

Chinese foreign ministry spokeswoman Hula Chunking expressed regret at the U.S. decision, but would not directly say if China had or had not been granted an exemption.

Oil markets have been anticipating the sanctions for months and the world's biggest producers have been increasing output.

Joint output from the world's top producers - Russia, the United States and Saudi Arabia - in October rose above 33 million bpd for the first time, up 10 million bpd since 2010.

In the Middle East, Abut Dhabi National Oil Co (ADNOUN) plans to increase its oil production capacity to 4 million bpd by the end of 2020 and to 5 million bpd by 2030, ADNOUN said on Sunday, versus current output of just over 3 million bpd.

(Reporting by Christopher Johnson in London and Henning Gloystein in Singapore; editing by Jason Neely)

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)