San Ysidro High School has received its sixth and seventh reported threat in two weeks, police said.
The school received two separate threats Wednesday morning, one aimed at the principal and another at the school as a whole, Principal Hector Espinoza said.
The phone-in threat came in at about 8:45 a.m. Wednesday morning, the San Diego Police Department said.
Police said they found the threats unsubstantiated. There was no lockdown.
The last such threat came in Monday afternoon and police did not lock down the school in response to that threat.
Officers cleared the area.