On Friday, a large number of nurses in Minnesota and California declared plans to walk out from the job for a single day next month if they do not arrive at contract agreements with hospices.

The nurses, 12,000 in the Minneapolis region and almost 13,000 at hospitals throughout California, both have fixed June 10 as a strike date. The protest is said to be the biggest in U. S. history.

Nurses in California say that low recruitment levels are their chief area of concern. While in Minnesota, nurses quoted that salary and pension problems are reasons for taking up a strike last week.

On Friday, the Minnesota nurses said that giving a notice of aim to strike was essential to get the hospitals to advance to compromises.

Nellie Munn, a registered nurse at Children's Hospital in Minneapolis and a representative, said, "There is no way to meaningfully negotiate when one side doesn't show up".

Maureen Schriner, a Spokeswoman for the Minnesota hospitals, said that the strike notice "clearly shows the union is interested only in a strike and has demonstrated that it does not want to negotiate in good faith".

She said that the hospices would specify their plans to answer a strike next week.