Oil prices were mixed on Tuesday, as the market has expected increasing U.S. oil inventories, and OPEC hinted at a possible extension of the ongoing output cut deal into the second half of the year.

U.S. crude oil inventories were forecast to have risen last week, according to the latest Reuters poll. The forecast came before official weekly data on U.S. oil stockpiles is set to be released by the U.S. Energy Information Administration on Wednesday.

OPEC and its allies have signaled that it would be possible to extend the ongoing supply reduction deal of 1.2 million barrels per day, which will expire in June, in accordance with market conditions.

Saudi Arabia's Energy Minister Khalid al-Falih said Monday that April would be too early to consider the extension decision, yet they would continue making efforts to seek a balanced market, according to S&P Global Platts.

"The consensus we heard ... is that April will be premature to make any production decision for the second half," he said. "As long as the levels of inventories are rising, and we are far from normal levels, we will stay the course, guiding the market towards balance.

The West Texas Intermediate for April delivery decreased 0.06 U.S. dollar to settle at 59.03 dollars a barrel on the New York Mercantile Exchange, while Brent crude for May delivery increased 0.07 dollar to close at 67.61 dollars a barrel on the London ICE Futures Exchange.