Brent crude was down 62 cents at $44.07 per barrel at 1439 GMT, while US crude declined by 63 cents to $41.54.
The Organization of the Petroleum Exporting Countries also said top exporter Saudi Arabia kept output steady in March - a sign Riyadh is serious about a plan to be discussed this weekend to freeze output and support prices - while OPEC supply overall rose only slightly.
"Ultimately, the downside based upon inventory figures is limited because of two factors: the strong gasoline demand and falling US crude production", said Anthony Headrick, energy market analyst at CHS Hedging. Gasoline fell by 4.2 million barrels to 239.76-million, compared with an analyst forecast for a 1.4-million-barrel draw.
Iran's oil minister won't attend the gathering of producers in Doha on April 17 and will instead send a representative, Seda reporter Reza Zandi said in a Twitter posting.
OPEC's view contrasts with that of the U.S. Energy Information Administration, which on Tuesday raised its demand forecast slightly.
When the U.S. light sweet crude oil futures for the spot month, also known as West Texas Intermediate (WTI) resumed the downward spiral in a rapid pace following a breakdown from the US$30 psychological level in January, many people pressed the panic button and set their minds for a lower-for-longer price scenario. Brent crude for June was trading five cents, or 0.12 percent, lower at $42.78.
So, could it be true, could the world's big oil producers come to their senses and cap production? Brent to over $43 a barrel and WTI to over $40 a barrel.
Speaking exclusively to the ABC's The Business, Gazprom deputy chairman Alexander Medvedev said he had only heard news reports of the deal between the two governments.
Further, comments by Saudi oil minister Ali al-Naimi in the al-Hayat newspaper put oil prices under pressure, as he confirmed his country's position that a complete production cut was out of the question.
However, Iran, whose oil production was restricted by worldwide sanctions imposed over its nuclear program, is unlikely to join the freeze as it aims to raise its output to its pre-sanctions level.
Yet major producers have continued to pump, pushing the global glut - the difference between crude supply and demand - to 2.5 million barrels per day in the first quarter of 2016, up from 2 million in the fourth quarter of previous year. He pointed out that Saudi Arabia is the only country that can increase its output.