* Aliyev accuses BP of "false promises" on oil output
* Clarifications expected to be made next week
BAKU, Oct 12 (Reuters) - BP Plc , accused of leaving Azerbaijan short of $8 billion in budget revenue with false promises on production from a major group of oil fields, has agreed to work with the Azeri state oil company to address falling output, a source said.
"A joint working group is being set up, which will try to look into reasons for the decline in oil output and to find a solution," an official from state oil company SOCAR, who did not want to be named, told Reuters.
"Clarifications over this issue may follow next week," he added.
BP, which has said it remains committed to its Azeri operations and would work with SOCAR to resolve the output issues, declined comment.
Azeri President Ilham Aliyev accused BP of "grave mistakes" in planning at the Azeri-Chirag-Guneshli (ACG) fields, which contain an estimated 1.2 billion tonnes of crude oil, in recent years.
The BP-led consortium which has invested $28.7 billion in Azerbaijan since the 1990s is holding talks with the country on whether it can extend the contract and work on the fields after 2024.
ACG was supposed to produce more than 1 million barrels per day (bpd) after a third phase was completed in 2008 but has not lived up to expectations.
After hitting 823,000 bpd in 2010, output has fallen, averaging 684,000 bpd in the first half of this year
(Reporting by Lada Yevgrashina; Writing by Margarita Antidze in Tbilisi; Editing by David Holmes)
Keywords: AZERBAIJAN BP/