Adds background throughout, Chevron statement

MOSCOW, May 29 (Reuters) - Oil production at the Chevron CVX.N-led Tengiz field, Kazakhstan's largest, fell sharply on May 26 as a result of an accident, two industry sources told Reuters on Friday.

The first two sources said daily output at Tengiz, which had only just recovered from a previous incident, fell to between 5,000 metric tons and 10,000 tons on Tuesday, compared with the usual level of 125,000 tons or 995,000 barrels.

Speaking on condition of anonymity due to the sensitivity of the situation, the sources did not give any details of the accident or its cause, but said they expected oil production to be gradually restored within roughly a week.

A third source said output at the field had climbed back to around 82,000 metric tons on May 27.

Chevron in a statement on Friday said part of the Tengiz oilfield had experienced "minor operational disruption" on May 28 and that output was being restored. It did not give further details.

Kazakhstan produces 2% of the world's daily supply of crude oil. It is mainly exported via the Caspian Pipeline Consortium to Russia's port of Novorossiysk.

A prolonged outage would add to uncertainty on global oil markets, where prices last month hit highs well over $120 a barrel LCOc because of disruption caused by the Iran war and the closure of the Strait of Hormuz.

Production at the Tengiz field, located near the Caspian Sea in the far west of Kazakhstan, was only fully restored by April after output was halted in January following an issue involving power distribution.