SANTA ROSA (AP) — Nurses at Sonoma County's Santa Rosa Memorial Hospital walked picket lines on Sunday in the second day of a planned three-day strike protesting wage offers and other issues.

Most of the nearly 660 nurses represented by the Staff Nurses' Association walked off the job early Saturday, union president Sue Gadbois said.

Union representatives and hospital officials continue to disagree over a number of issues, including pay and staffing levels. The issue of compensation could have "a very negative impact on the hospital's ability to retain and attract nurses," she said.

Hospital officials have noted that they are run by the nonprofit group, St. Joseph Health-Sonoma County, and that the hospital doesn't post profits or reward shareholders. Costs must be controlled because of tighter operating margins and anticipated reductions in government health care reimbursements, officials said.

"The hospital has engaged and continues to engage in good faith bargaining with our registered nurses," hospital spokesman Debra Miller said. "We anticipate reimbursement rates going down, and we have asked our nurses to share in some of the cost savings."

The nurses were joined in the strike by members of the Stationary Engineers union who represent engineers at the hospital and at nearby Petaluma Valley Hospital.

The strike is set to end Tuesday morning, but the nurses are expected to be "locked out" until Thursday because the hospital has hired replacement nurses, who are contracted to work for five days.

The walkout comes after nurses at the hospital went on strike in early October, the first strike at the hospital since 1986.

In a separate strike last week, registered nurses represented by the California Nurses Association walked off the job Thursday at seven Sutter hospitals in Alameda, Contra Costa and Solano counties as part of a one-day strike.

The walkout was the sixth strike organized by the group in a lingering contract dispute with Sutter. The last walkout was in July.