A "limited fire" broke out on a subsidiary oil pipeline in eastern Saudi Arabia on Saturday after assailants fired shots at a security patrol, the state news agency SPA said.
An industry source told Reuters there was no impact on oil operations in the world's top crude exporter.
SPA, citing the spokesman for police in Eastern Province, said authorities were at the scene quickly and had put out the fire.
It said the incident happened at 2:00 a.m. local time on Saturday (2300 GMT Friday), when the patrol came under fire at the entrance of Awamiya in Qatif district.
Saturday's incident followed a similar one last month when a small fire broke out on a gas pipeline in the oil-rich Eastern Province.
Earlier this week, a Saudi judge sentenced to death prominent Shi'ite cleric Nimr al-Nimr who had called for greater rights for the kingdom's Shi'ites.
The sentencing was seen as possibly raising tensions in Qatif, which has historically been the focal point of anti-government demonstrations in support of Shi'ites, but where the frequency of protests has died down over the past year.
Hundreds of people in Qatif had staged a march in solidarity with Nimr, a local resident said shortly after the sentencing.
There have been no confirmed attempts by Shi'ite activists to target Saudi Arabia's energy facilities. State oil firm Saudi Aramco is a major employer of Shi'ites in both Qatif and the sect's other main population centre in Eastern Province, al-Ahsa..