Brent crude future prices rose above $61 a barrel on Thursday, as investors brushed aside bearish U.S. inventories data to focus on the lack of a deal in talks over Iran's nuclear program.

Tehran's ambassador to the International Atomic Energy Agency (IAEA) said on Wednesday no deal had been reached on the duration of any possible final agreement with world powers on Iran's program. That allayed investors' fears of an imminent rise in Iranian oil supply.

Brent LCOc1 has traded around $60 since mid-February, rebounding from a six-year low of about $45 hit in January.

Brent crude front-month futures rose 77 cents to $61.32 a barrel by 4.59 a.m. ET while West Texas Intermediate (WTI) crude CLc1 rose 65 cents to $52.18.

A two percent gain in the previous session narrowed WTI's spread with global benchmark Brent to just above $9 a barrel.

"We're trading in a new range. At the moment that range for Brent is $56-$62 for WTI its $47-$54, and I think we're looking to stabilize," said Michael Hewson, chief markets analyst at CMC Markets.

"We'll continue to do so until such time as we get some indication that demand is starting to outstrip supply and I don't think we're there yet."

Government data showed commercial crude stockpiles in the United States hit a record high, rising twice as much as expected to 10.3 million barrels last week, but that failed to push prices down.

"The rate of stock build has accelerated week by week throughout February and with upcoming refinery maintenance likely to weaken demand for crude, it is possible that this will continue in March," BNP Paribas analysts said in a note.

Saudi Arabia's oil minister voiced cautious optimism about the market outlook on Wednesday, saying he expected oil prices to stabilize.

A deteriorating security situation led Libya's state oil company to declare force majeure on 11 of its oilfields on Wednesday.

Output from the OPEC producer was at more than 400,000 barrels per day on March 1, higher than in January but well below the 1.6 million bpd levels seen before the country's 2011 civil war.

"The situation is not really improving and oil installations are increasingly being the subject of a fight for power," said Olivier Jakob, oil analyst at Swiss consultancy Petromatrix.