The United Arab Emirates (UAE) produced 2.5 million barrels per day (bpd) of crude oil in September, down from around 2.6 million bpd in August, a Gulf oil source said on Monday. Leading oil exporter Saudi Arabia raised its output by around 918,000 bpd to 9.81 million bpd in June after failing to convince exporter group OPEC to agree a formal increase to compensate for a lack of Libyan oil. As the world economic outlook darkened in the months that followed, prompting OPEC to revise down its demand forecast, Saudi Arabia cut to 9.39 mln bpd in September, while the UAE cut output by around 100,000 bpd month on month. "Production for September was 2.5 million (bpd). This is slightly lower than the previous month because of a small decrease in demand," the source told Reuters giving no further details. Benchmark Brent crude LCOc1 oil prices fell sharply in September on growing European debt crisis fears and the prospect of some Libyan oil returning to market. Libyan oil output has recovered to around 400,000 bpd, around a quarter of its pre-war production rate, pressuring Gulf producers to trim their production.