The Greene County Courthouse was one of at least 30 in Tennessee targeted by false bomb threats Tuesday.

No devices were found in any of the courthouses targeted by the calls, authorities said.

A telephone call came in about 11 a.m. Tuesday to the County Clerk's office in the Courthouse Annex building on Cutler Street, prompting evacuation of both the annex and the Greene County Courthouse, on South Main Street.

Both buildings were searched, and employees and clients were backin both by 1 p.m., Sheriff Steve Burns said.

The call threatened the presence of "multiple explosives," Burns said.

Other area courthouses receiving similar calls included those of Blount, Carter, Claiborne, Hamblen and Hancock counties, Burns said.

Statewide, at least 30 courthouses received bomb threat calls, Tennessee Department of Safety and Homeland Security spokeswoman Dalya Qualls said.

"We're working with multiple agencies," Burns said.

Because of the volume of calls, "It appears it's possible it was a computerized threat or hoax of some kind," Burns said.

"Whoever orchestrated this call probably thought the clerk's office was in the courthouse," Burns said.

Burns said people who work in both buildings were told to take an early lunch. Others who had business at the courthouse or annex waited outside until they were given the all-clear to go back inside.

"We went through it," Burns said, adding, "[The courthouse] is secured from early morning to evening, so it would be hard to get anything in there anyway."

Courthouses in surrounding counties all received phone calls with similar messages at about the same time, opening up the possibility of a computer-generated hoax, Burns said.

"It appears that the messages were similar in all of them, so it's possible it's the same [source]," he said.

The Greene County Courthouse was evacuated until 12:30 p.m., according to the Sheriff's Department.

One witness, Christopher Seaton, said he overheard "bomb threat," when the building was evacuated.

Seaton, an attorney with Quest Conflict Resolution, said he overheard an exchange between what he said was the chief of security and someone else.

"The chief of security came in and whispered loudly, 'everyone needs to go to lunch now,'" Seaton said.

Jeremy Clementi was at the courthouse for a hearing. He said his case was scheduled to start at 11 a.m., but before the hearing could begin, an officer came in and spoke to the judge.

Clementi said that those in the courtroom were told to leave immediately, but were not given a reason.

Clementi was surprised about the bomb threat rumors, which he said is unusual for Tennessee.

"I'm originally from Florida," Clementi said. "Florida -- that's a different story. There is a bomb threat every day."

Burns said similar threats may have been made recently at courthouses in several other states, including Nebraska, Oregon and Washington.

Qualls said that there were 14 bomb threats in East Tennessee, nine in West Tennessee counties and seven in Middle Tennessee.

The threats prompted the evacuation of many of the buildings. No bombs were found, Qualls said.

Tennessee is at least the fourth state to contend with the fake bomb threats, the Associated Press reported.

In Oregon, 28 courthouses were threatened last week, and similar threats were reported in Nebraska and Washington.

"At this time, these incidents are being handled by local law enforcement agencies.

"The Tennessee Highway Patrol is assisting local law enforcement agencies, as needed. So far, there have been no devices found at this time," Qualls said late Tuesday afternoon.

Staff Writer Lauren Henry contributed to this report.