Crude futures slipped in Asian trade on Tuesday as investors took profits after prices climbed more than 3 percent in the previous session.

The dollar was also weighing on prices after rising against a basket of currencies .DXY, while a Reuters poll showed a build in US crude stockpiles last week.

Major oil producers are gathering in Algeria for a three-day meeting that could see moves to cut or freeze oil output in an effort to support oil prices.

The Organization of the Petroleum Exporting Countries and other oil producers led by Russia are meeting informally on the sidelines of the International Energy Forum in Algeria from Sept. 26-28.

But markets remained sceptical that producers would reach a deal, said Michael McCarthy, chief market strategist at Sydney's CMC Markets.

"The dominant news for investors is US inventory data unless we see something surprising out of Algiers," he said.

The reversal in oil prices during the Asian time zone on Tuesday meant investors were generally profit-taking, McCarthy said.

Broader markets were focused on the first US presidential debate between Democrat Hillary Clinton and Republican Donald Trump.

US West Texas Intermediate (WTI) crude CLc1 had fallen 38 cents to $45.55 a barrel by 0103 GMT, after rising $1.45, or 3.3 percent, in the previous session.

Brent crude futures LCOc1 slipped 43 cents to $46.91 a barrel after closing up $1.46, or 3.2 percent.

"The rise started in the Asia Pacific so it was a bit of a slow burn," McCarthy said.

US commercial crude oil stocks likely rose by an average of 2.8 million barrels to 507.4 million barrels in the week to Sept. 23, reversing three weeks of unexpected drawdowns, a Reuters poll of seven analysts showed.

That came ahead of weekly inventory reports from industry group the American Petroleum Institute (API) that will be released later on Tuesday, and the US Department of Energy's Energy Information Administration (EIA) that will be published on Wednesday.

"With the market still unconvinced an agreement will be reached, any signs that OPEC will cap output could see prices surge higher," said ANZ in a market report on Tuesday.

OPEC member Iran on Monday downplayed the chances of oil producers clinching an output-restraint deal although several other producers, including the United Arab Emirates and Algeria, hoped measures could be agreed to curb output.

That came as U. Energy Secretary Ernest Moniz said on Monday that Iran's oil exports are roughly back to the same level they were before international sanctions were imposed over the Tehran's nuclear programme.

But in a reflection of the impact from lower oil prices, which have more than halved from 2014 levels, Saudi Arabia will cut ministers' salaries by 20 percent, Riyadh announced.