Hints from Wednesday's meeting of OPEC ministers in Vienna of a balanced market in the second half of the year sent crude oil prices tumbling in early trading.

Members of the Organization of Petroleum Exporting Countries are arriving in Vienna for a series of meetings to review the status of the oil markets after nearly a year of lower prices. Crude oil is down roughly 40 percent from June.

Qatari Energy Minister Mohammed bin Saleh al-Sada told delegates Wednesday there were signs of continued economic growth and future demand.

"The global economic recovery is showing encouraging signs, oil demand is improving," he said in his address. "Indeed, going by current trends, there should be a more balanced market in the second half of the year."

OPEC in November opted to keep production steady despite the bear market for crude oil. That sent prices tumbling below the $50 mark as the market tilted more heavily toward the supply side.

In his speech, OPEC Secretary-General Abdullah al-Badri said the 12-member group was committed to playing an active role.

"OPEC's commitment to market order and stability is unwavering," he said. "It has a long tradition of supporting collective dialogue among producers and between the producers and consumers."

Market analysts this week said they expected OPEC to hold steady when considering production levels later this week.

Brent crude oil prices were down 1.7 percent from the previous close to $63.34 per barrel. West Texas Intermediate, the U.S. benchmark, fell 2 percent to $60.01 per barrel for the July contract.

OPEC said demand for oil should increase by 18 million bpd by 2040. The OPEC secretary-general, however, said oil may not hold the pole position in the energy sector for long, noting diversity is essential to meeting long-term future energy demands in a sustainable way.

Crude oil prices have struggled to move much beyond the $60 market on signs global economic momentum was slow.

The U.S. Commerce Department said the trade deficit declined from March levels that were the highest since 2008. U.S. Federal Reserve Chair Janet Yellen warned last month, however, the U.S. economy was still facing headwinds.