Brent crude futures fell 26 cents to $67.24 a barrel by 1337 GMT, while US West Texas Intermediate crude eased 32 cents to $63.59.

The American Petroleum Institute releases its weekly figures on US crude inventories later on Tuesday. Stocks are forecast to have risen by 2.7 million barrels last week, according to a Reuters poll.

Inventories have fallen by more than 100 million barrels, or a quarter, in the last 12 months, to around their lowest in three years. Seasonally, stocks tend to build in the first three months of the year.

Soaring US production is upending global oil markets at a time when other major producers - including Russia and the Middle East-dominated Organization of the Petroleum Exporting Countries - have been withholding output to prop up prices.

The United States will overtake Russia as the world's biggest oil producer by 2019, International Energy Agency (IEA) Executive Director Fatih Birol said on Tuesday.

"US shale growth is very strong, the pace is very strong ... The United States will become the No.1 oil producer sometime very soon," he told Reuters separately.

US output was 10.27 million barrels per day (bpd), according to government data released last Thursday, higher than the latest figures for Saudi Arabia, the world's largest exporter, and just below Russia.

A steadier dollar also undermined the crude oil market, given the inverse relationship between the two, whereby a stronger US currency can encourage investors to book profits on their holdings of dollar-priced commodities, stocks or bonds.

"Our technical analysts are saying (oil) is bearish unless we break above $67.70," SEB head of commodity strategy Bjarne Schieldrop said.

"It's been rejected exactly at that level ... and that is where the price action is today. It's at a level where it's a tie between 'back to bullish or back to bearish'."