Law enforcement officials on Sunday evening were searching for the cause of a loud boom heard in several communities across Gregg County.

The city of Gladewater issued a social media alert at 6:37 p.m. Sunday, saying that emergency dispatchers were aware of a boom heard as far away as Longview, and that the city’s police and fire departments were out monitoring but that nothing was known at this time.

Longview police spokeswoman Kristie Brian and Gregg County Sheriff’s Lt. Josh Tubb said they had heard unconfirmed reports of a possible incident in Upshur County near Gladewater but that they had no further information.

A call to the Upshur County Sheriff’s Office seeking more information was not immediately returned.