Crude oil prices traded slightly lower early Monday as supply strains built up against expectations of some form of cut from major producers next month.

The Iranian Oil Ministry's news website Shana reports Iran exported around 14 million barrels of crude oil to European buyers since January, when sanctions pressures started to relax in response to last year's multilateral nuclear agreement. Iran since January has sought to regain a market share lost in the four years since the European Union slapped sanctions on the country's energy sector.

Crude oil prices are under pressure from a market tilted heavily toward the supply side, a trend that emerged in recent years because of U.S. oil production and compounded in 2016 by the return of Iran.

In a trading day lightened by observations for the Easter holiday, Brent crude oil prices moved lower by 0.5 percent to start the day at $40.22 per barrel. West Texas Intermediate, the U.S. benchmark for crude oil prices, was off by 0.3 percent to open in New York at $39.35 per barrel.

Iran is one of the largest contributors to production from the Organization of Petroleum Exporting Countries. Saudi Arabia, an Iranian rival, has joined Russian and other non-OPEC members in calling for a meeting in April to consider freezing production at January levels in order to stabilize the price of oil, down heavily from peak 2014 levels above $100 per barrel.

Pointing to a regional economic market report, the official Kuwaiti News Agency reported any formal agreement would not have a dramatic impact on supply and demand dynamics.

"If the agreement takes place, its effect will be limited, as the countries involved are already producing near record levels," the report read.

Monday's soft open, meanwhile, was supported by an outlook from the U.S. Energy Information Administration, which said in recent productivity report oil production from domestic shale reserve areas should decline in April.