Oil prices were mixed Friday after recent declines, but it is the first weekly drop in six weeks under the weight of rising US supplies.

At 06:16 GMT, the price of crude for global benchmark Brent was $61.23 a barrel, down 13 cents from the previous close.

US crude was $55.32 a barrel, up 18 cents. Traders said strong US crude exports were driving West Texas. Lamsa crude last week was the highest level since 2015.

Crude markets have received general support in recent months from OPEC, which has been curbing production with some non-member producers such as Russia since January to reduce market supply and support prices.

This has led to a 40% rise in Brent prices since June.

The ABN Amro said that the agreement to reduce production between some OPEC oil producers and beyond has led to a drop in inventories and a recovery in oil prices, so we expect in 2018 the continuation of the oil price rally towards $75 a barrel.

The curbing agreement ends in March 2018, but Opec will meet on November 30 to discuss the policy. Analysts say more production constraints are needed to reduce supply oversupply.

“The problem is that oil stocks are still above the five-year average,” said William Olochlin, investment analyst at Reifen Australia Securities.