Update, 1:20 p.m.: A “suspicious item” found during an investigation of a bomb threat at Annandale High School posed no danger, police said after examining the item.

Meanwhile, parents continued to voice frustration with the school system’s handling of the situation.

Mary Wilmoth, parent of an Annandale sophomore, said she drove her son to school when he missed the bus Friday. They were turned away by police, she said, who told them to go home and return in two hours.

Wilmoth said it was nearly 10 a.m. before she received official notification from the high school about the situation. Meantime, she relied on Twitter and Facebook updates — including from the student newspaper — to find out what was happening, she said.

Ultimately, she gave up waiting and took her son to work with her, she said.

“It seemed really late when we started getting information,” she said.

Original post: A bomb threat closed Fairfax County’s Annandale High School for nearly three hours Friday morning and interrupted bus transportation for 18 elementary schools, school and police officials said.

Police found a “suspicious item” in the school’s front yard while conducting a security sweep with robots and bomb-sniffing dogs, said police spokesman Bud Walker. The item is being examined.

Meanwhile, students have been allowed to enter the building and the principal intends to go ahead with classes, said school system spokesman John Torre. Today is the last day before spring break.

The threat was called into the WJLA television station about 4:30 a.m., Walker said.

Students arriving for school — which normally begins at 7:20 a.m. — were held in their school buses while police swept the building. About 10 a.m., officers began allowing students and faculty into the rear of the school.

The Annandale school buses usually drop students off and then turn around to pick up kids headed to nearby elementary schools, which generally start later in the morning.

With the Annandale buses out of commission Friday morning, pickup was delayed for students at 18 elementary schools. The school system sent e-mail and phone alerts to affected families, and encouraged bus riders to come to school by other means if possible.

On Facebook, some parents complained that the school system’s communication was too slow.

“It’s understandable given the situation that parents would express concerns,” Torre said. The students “were safe and secure at all times,” he added.

This post has been updated since it was first published.