Published: Nov 10, 2010 11:53 PM EST
Updated: Nov 10, 2010 1:43 PM EST

PEMBROKE PINES, Fla. (AP) - Florida authorities lifted the lockdown of all schools in the nation's sixth-largest district Wednesday after police said the credibility of a threat made against students had diminished.

An unidentified woman called a radio station earlier in the day, saying her husband might go to a school and start shooting, police said.

 "Schools are dismissing normally, but there will still be police presence," Pembroke Pines Police Capt. Daniel Rakofsky said. He did not elaborate on why the threat had diminished.

Broward Superintendent James Notter said the threat included hate words, apparently against certain ethnic and religious groups.

Police said that although the district chose to lockdown schools, other government buildings stayed open. Many have their own security on site.

Schools in Pembroke Pines, a suburb of Fort Lauderdale, were initially placed on lockdown as a precaution, and police in bullet-proof vests guarded at least some entrances. Then the lockdown was then extended to all 300 Broward County schools. The county has nearly 257,000 students.

Neither the man nor the woman have been identified, though police said they were following several leads. Authorities would not identify the radio station.

Nervous parents flooded telephone lines and showed up at schools as word of the lockdown spread.

Irma Hernandez had tears in her eyes as she and her husband waited outside Charles W. Flanagan High School, where her 15-year-old son is a student.

"We're just nervous, scared," she said. "We don't know what's going to happen."

Broward County Schools spokeswoman Nadine Drew said schools continued operating as normally as possible. In addition to a police presence at normal dismissal, all after school activities were canceled.

The county has the state's second-largest school district.