Saudi Arabia produced 9.780 million barrels per day (bpd) of crude oil in June, up from 9.705 million bpd in May, an industry source familiar with the matter said on Wednesday.

The world's largest oil exporter and Opec heavyweight supplied 9.745 million bpd to the market, the source said. Supply to the market may differ from production depending on the movement of barrels in and out of storage.

The source did not give a reason for the rise in output, but the kingdom typically increases production during the hot summer months to meet a surge in electricity demand.

Demand for power generation oil in Saudi Arabia is usually higher in June than in May, official data from recent years shows.

Opec's oil output has fallen in June from May's three-month high, a Reuters survey found last month, as fighting in Iraq closed its largest oil refinery and technical problems slowed its southern exports.

Supply from the Organization of the Petroleum Exporting Countries has averaged 29.93 million bpd, down from 30.00 million bpd in May, according to the survey based on shipping data and information from sources at oil companies, Opec and consultants.-Reuters