Brent crude futures were at $74.69 per barrel at 6:46am GMT, down 65 cents, or 0.9%, from their last close. Meanwhile, Nigeria's Bonny Light crude oil has maintain an worldwide price of $73.44 per barrel, higher than the Organisation of the Petroleum Exporting Countries (OPEC) basket price of $73.35 per barrel.
Three OPEC sources told Reuters a technical panel - the organisation's economic commission - met on Monday to review the market outlook and present it to member countries' oil ministers later in the week.
However, in late May, oil prices dropped in light of the reports about a possible relaxation of conditions of the OPEC-non-OPEC deal.
Smith says USA oil production is poised to hit 12 million barrels a day next year.
Crude oil demand now outstrips supply, and Opec members will debate whether to lift the 18-month-old production cap to stabilize prices.
Resistance is being led by Iran, deeply wary of any move by regional rival Saudi Arabia that could push down oil prices at a time when Tehran faces renewed sanctions following US President Donald Trump's decision to quit its global nuclear deal, which is likely to send the country's oil exports plummeting.
BCC blamed the downgrade on the uncertainties around Brexit, interest rate hikes, trade war risks and rising oil prices.
"The market is well-supplied, and OPEC should abide by its decision up to the end of the year", he said.
The IEA monthly report stated that oil market is finely balanced and vulnerable to disruption and said OPEC swing producers and others might need to raise their production, even as it noted some factors on the demand side are likely to have a moderating influence.
There is no incentive for those countries to agree to an increase in OPEC's production because they have no capacity to respond to one. Iran and Venezuela production for example continue to dwindle due to United States sanctions. After writing to OPEC and calling for the organization's support for members targeted by sanctions, Iran, along with Venezuela and Iraq, is going to veto Saudi Arabia and Russia's proposal at the June 22 meeting. Several OPEC countries are not able to increase the production. On one side, under the US influence [either in the form of alliance or sanctions] Saudi Arabia and non-OPEC-member Russian Federation, which had a significant role in reaching the deal, are said to be willing to ease the production cap and use some of their spare capacities.
Falih said the oil market had now rebalanced and his aim was to prevent a shortage of crude in future that could squeeze the market.
The FTSE 100 edged eight points, or 0.1% lower, to 7,626, failing to reverse the 1.7% slide on Friday after president Trump said 25% tariffs on $50 billion of Chinese imports would go ahead next month, provoking a promise of retaliation from China. Meanwhile, traders are trying to digest the impact from both the United States and China issuing tarrifs on goods and the threat of a broader trade war between the world's two largest economies.