LONGVIEW, Wash. (AP) — Hundreds of Longshoremen stormed the Port of Longview early Thursday, overpowered and held security guards, damaged railroad cars, and dumped grain that is the center of a labor dispute, said Longview Police Chief Jim Duscha.

Six guards were held hostage for a couple of hours after 500 or more Longshoremen broke down gates about 4:30 a.m. and smashed windows in the guard shack, he said.

No one was hurt, and nobody has been arrested. Most of the protesters returned to their union hall after cutting brake lines and spilling grain from car at the EGT terminal, Duscha said.

The International Longshore and Warehouse Union believes it has the right to work at the facility, but the company has hired a contractor that's staffing a workforce of other union laborers.

Thursday's violence was first reported by Kelso radio station KLOG.

Police from several agencies in southwest Washington, the Washington State Patrol and Burlington Northern Santa Fe responded to the violence to secure the scene that followed a demonstration Wednesday.

"We're not surprised," Duscha said. "A lot of the protesters were telling us this in only the start."

One sergeant was threatened with baseball bats and retreated, Duscha said. "One officer with hundreds of Longshoremen? He used the better part of discretion."

The train was the first grain shipment to arrive at Longview. It arrived Wednesday night after police arrested 19 demonstrators who tried to block the tracks. They were led by ILWU International President Robert McEllrath, who said they would return.

The blockade appeared to defy a federal restraining order issued last week against the union after it was accused of assaults and death threats.

EGT chief executive Larry Clarke said it was unfortunate that law enforcement needed to make arrests.