OAKLAND, Calif. - Thousands of Occupy Wall Street protesters blocked cargo trucks at some of the West Coast's busiest ports Monday.

The protests stretched from San Diego to Anchorage, Alaska, brought work to a standstill in Oakland, Calif., and Longview, Wash., and led to the closure of a major marine terminal in Portland, Ore.

Organizers declared victory and promised more demonstrations to come.

"The truckers are still here, but there's nobody here to unload their stuff," protest organizer Boots Riley said. "We shut down the Port of Oakland for the daytime shift, and we're coming back in the evening. Mission accomplished."

Organizers called for the "Shutdown Wall St. on the Waterfront" protests, hoping the day of demonstrations would cut into the profits of the corporations that run the docks and send a message that their movement was not over. The closures' economic impact, however, was not immediately clear.

The longshoremen's union did not officially support the protests, but its membership cited a provision in its contract that allowed workers to ask to stay off the job if they felt the conditions were unsafe. Some went home with several hours' pay, while others left with nothing.

Oakland Longshoreman DeAndre Whitten was OK with it. "I hope they keep it up," said Whitten, who lost about $500. "I have no problem with it. But my wife wasn't happy about it."

Others, such as the truck drivers who had to wait in long lines as protesters blocked gates, were angry, saying the demonstrators were harming the very people they were trying to help. "This is a joke. What are they protesting?" said Christian Vega. "We have jobs and families to support and feed," he said. "Most of them don't."

From Long Beach, Calif., up to Vancouver, British Columbia, protesters beat drums and carried signs as they marched outside the gates. There were a handful of arrests, but no major clashes with police.

The rain dampened some protests. Several hundred showed up at the Port of Long Beach and left after several hours.

The movement, which sprang up this fall against what it sees as corporate greed and economic inequality, is focusing on the ports as the "economic engines for the elite." It comes weeks after police raids cleared out most of their tent camps.

Protesters are most upset by two West Coast companies: port operator SSA Marine and grain exporter EGT.

Goldman Sachs Group Inc. owns a major stake in SSA Marine and has been a frequent target of protesters. They say they are standing up for workers against the port companies, which have had high-profile clashes with union workers lately.

Longshoremen in Longview, for example, have had a long-standing dispute with EGT.

In Seattle, police used "flash-bang" percussion grenades to disperse protesters who blocked an entrance to a Port of Seattle facility Monday evening.

Officers moved in after protesters tried to set up a makeshift barrier using scraps of wood, aluminum debris, and any other material they could scrape together.

After the grenades went off, the protesters scattered.