LOS ANGELES (AP) — Clerical workers and longshoremen at the nation's largest port complex will return to work Wednesday, eight days after they walked out in a crippling strike that prevented shippers from delivering billions of dollars in cargo across the country.

"I'm really pleased to tell all of you that my 10,000 longshore workers in the ports of LA and Long Beach are going to start moving cargo on these ships," said Ray Familathe, vice president of the International Longshore and Warehouse Union. "We're going to get cargo moved throughout the supply chain and the country and get everybody those that they're looking for in those stores."

Negotiators reached a tentative agreement to end the strike late Tuesday, less than two hours after federal mediators arrived from Washington, D.C. No details about the terms of the deal were released, though a statement from the workers' union said it had won new protections preventing jobs from being outsourced.

Days of negotiations that included all-night bargaining sessions suddenly went from a stalemate to big leaps of progress by Tuesday. Mayor Antonio Villaraigosa said the sides were already prepared to take a vote when the mediators arrived.

At issue during the lengthy negotiations was the union's contention that terminal operators wanted to outsource future clerical jobs out of state and overseas — an allegation the shippers denied.

Shippers said they wanted the flexibility not to fill jobs that were no longer needed as clerks quit or retired. They said they promised the current clerks lifetime employment.

The strike began Nov. 27, when 450 members of the union's local clerical workers unit walked off their jobs. The clerks had been working without a contract for more than two years.

The walkout quickly closed 10 of the ports' 14 terminals when some 10,000 dockworkers, members of the clerks' sister union, refused to cross picket lines.

Even though the deal was reached soon after their arrival, the federal mediators said they had little to do with the solution.

"In the final analysis, it worked. The parties reached their own agreement, said George Cohen, director of the Federal Mediation and Conciliation Service. "There is no question in my mind that collective bargaining is the best example of industrial democracy in action."

During the strike, both sides said salaries, vacation, pensions and other benefits were not a major issue.

The clerks, who make an average base salary of $87,000 a year, have some of the best-paying blue-collar jobs in the nation. When vacation, pension and other benefits are factored in, the employers said, their annual compensation package reached $165,000 a year.

"We know we're blessed," one of the strikers, Trinnie Thompson, said during the walkout. "We're very thankful for our jobs. We just want to keep them."

Union leaders said if future jobs were not kept at the ports, the result would be another section of the U.S. economy taking a serious economic hit so that huge corporations could increase their profit margins by exploiting people in other states and countries who would be forced to work for less.

Combined, the Los Angeles and Long Beach ports handle about 44 percent of all cargo that arrives in the U.S. by sea. About $1 billion a day in merchandise, including cars from Japan and computers from China, flow past its docks.

Shuttering 10 of the ports' 14 terminals kept about $760 million a day in cargo from being delivered, according to port officials. The cargo stacked up on the docks and in adjacent rail yards or, in many cases, remained on arriving ships. Some of those ships were diverted to other ports along the West Coast.

After the deal was reached, the ports' management said they were "delighted that the terminals will be operating again, that the cargo will be flowing."

The clerks handle such tasks as filing invoices and billing notices, arranging dock visits by customs inspectors, and ensuring that cargo moves off the dock quickly and gets where it's supposed to go. The $1 billion a day in cargo that moves through the busy port terminals is loaded on trucks and trains that take it to warehouses and distribution centers across the country.

Villaraigosa, who had been calling for the two sides to reach a deal for days, said he was pleased by the resolution.

"I think it's appropriate to say 'mission accomplished,'" he said.