A bomb threatening note was found Thursday at a high school in the US state of Texas, prompting an early release of students, local media reported.

The note was found by a student in a boys' bathroom at the Highland Park High School. School authorities had notified the police in University Park city, the Dallas Morning News reported.

A similar note was found Wednesday at the same place, according to district spokesman Helen Williams.

The police has searched the building with bomb-sniffing dogs and found no imminent safety threat. School officials said they would beef up security on Friday and continue to look for suspects.

The district's communication specialist Jacki Moran sent notes to parents and staff saying "we will continue to monitor the campus closely, and we encourage parents to talk to their children about how seriously any threats, written or otherwise, are taken on campus."