LONDON, July 13 (Reuters) - Nigeria's Dangote oil refinery issued a spot tender for crude oil on Monday, a trade source said, while the wider market remained quiet.

• The refinery was inviting offers for crude oil to be loaded between August 1 and 30, a copy of the tender seen by Reuters showed.

• A lack of buying demand, particularly from China, has been weighing on the West African crude oil market and some grades like Middle Eastern and Latin American crudes have become cheaper for market participants.

• In the wider market, Nigeria's crude oil production rose to its highest level in more than six years in June, as stable operations and improved pipeline reliability boosted output, according to data released by the regulator on Sunday.