Thousands of workers at 14 hotels ended a two-week strike Wednesday, but operators imposed a lock-out until a contract dispute is settled.

Unionized workers who showed up at two hotels were met by police or security guards. The workers resumed picketing after managers said they were enforcing the work stoppage.

"Without an agreement, there is no assurance that union leadership won't call additional strikes," said Matthew Adams, vice president of the San Francisco Multi-Employer Group, which represents the hotels.

The union represents housekeepers, cooks, bell men and other service staff. The contract expired in August, and a work stoppage at four of the hotels began Sept. 29. The sides are scheduled to meet Thursday.

The hotels have been using replacement workers, many of them flown in from other properties with the same owners.

Sticking points in the negotiations include wages, health care premiums, pensions and the contract length. The hotels are seeking a five-year deal, while the union wants a two-year contract that would expire when hotel workers in other major cities are set to renegotiate their labor pacts.

Democratic vice presidential candidate John Edwards stopped by the picket line at the Argent Hotel on Tuesday night. Some picketers put down their signs and shook Edwards' hand. They changed their chants to "Thank you! Thank you!" as he pulled away.