Saudi Arabia has increased the price it charges customers for its crude oil for the first time in five months, undermining the argument that the kingdom has launched a price war with fellow members of the Opec oil cartel.

Saudi Aramco, the state-owned oil company, said it would sell its benchmark Arab light to customers in Asia at a discount of 10 cents a barrel to the Dubai/Oman contract in December, up from a discount of $1.05 in November.

Concerns about a global supply glut amid weaker demand drove benchmark oil prices to their lowest level in almost four years last month. Since reaching $115 a barrel in mid June, Brent, the international oil marker, has fallen 25 per cent, while West Texas Intermediate, the US equivalent, is down by a similar amount.