RIYADH, Feb 19 (Reuters) - Saudi Shi'ites have held a small protest in the kingdom's oil-producing eastern province, close to Gulf Arab neighbour Bahrain where unrest has cost six lives, local Shi'ite sources said on Saturday.

They said a group of Shi'ites staged a protest on Thursday in the town of Awwamiya, near the Saudi Shi'ite centre of Qatif on the Gulf coast, to demand the release of fellow Shi'ites held in prison without trial.

Top OPEC exporter Saudi Arabia fears that unrest in Bahrain, where majority Shi'ites are protesting against the Sunni government, might spread to its Shi'ite minority who mostly live in the eastern province, the source of Saudi oil wealth.