SINGAPORE (Reuters) - Saudi Arabia, the world's top oil exporter, on Sunday lowered crude oil prices for Asian buyers in May to their lowest in four months, after a shock decision by the OPEC+ oil group to increase supply on Thursday.

State oil company Saudi Aramco cut the May official selling price (OSP) for flagship Arab Light crude by $2.30 to $1.20 a barrel above the average of Oman and Dubai prices, a pricing document from the producer showed.

The company also lowered April prices for other grades it sells to Asia by $2.30 per barrel.

This is the second consecutive month Aramco has lowered its prices. Eight OPEC+ countries unexpectedly agreed on Thursday to advance their plan to phase out oil output cuts by increasing output by 411,000 barrels per day in May, a decision that prompted oil prices to extend earlier sharp losses.

Prior to the news, Arab Light price for Asia had been expected to fall by $1.80 to $2 in a Reuters survey, tracking the steep declines in benchmark prices in March.

Spot premium of Dubai averaged at $1.38 per barrel in March, down from $3.33 per barrel, the average in February following more Russian supply returning to Asia since March.

Saudi term crude supplies to

Asia are priced as a

differential to the Oman/Dubai

average:

May APRIL CHANGE

SUPER 1.75 4.05 -2.30

LIGHT

EXTRA 1.00 3.30 -2.30

LIGHT

LIGHT 1.20 3.50 -2.30

MEDIUM 0.65 2.95 -2.30

HEAVY -0.50 1.80 -2.30