A unknown transmission line problem knocked out power to 1,187 Entergy customers for more than 20 minutes Thursday, Entergy customer service representative Shelia McKinnis said.

She said power went out about 11:33 a.m. and was restored at 11:52 a.m. The affected area was south of Interstate 20 from the intersection of Mississippi 27 and U.S. 80 east to just past Mount Alban Road, although customers on the Cockrell Road, Riley Road and Sammy Young Road north of I-20 were also without power.

McKinnis said Entergy officials were investigating the cause of the problem.