Los Angeles, California - Thousands of Kaiser Permanente nurses and health care professionals are returning to work in California and Hawaii on Tuesday after a four-week strike.

"Over the past 48 hours, significant movement at the bargaining table prompted union leaders to send the employer a notice of unconditional return to work," the United Nurses Associations of California/Union of Health Care Professionals said in a statement.

"According to the union, returning members to their patients and their livelihoods is the clearest path to securing a final agreement and building on the progress achieved during the strike."

On January 26, around 31,000 employees walked out at two dozen Kaiser Permanente hospitals and hundreds of clinics across California and Hawaii, demanding fair wages and safe staffing levels.

Last October, more than 75,000 nurses and health care workers went on strike at Kaiser facilities in several states over stalled contract negotiations.

UNAC/UHCP had been bargaining with Kaiser since May. In December, company management left the bargaining table, prompting the union to file an unfair labor practice charge with the National Labor Relations Board.

According to the Associated Press, the health care professionals had been asking for a 25% wage increase over four years. The company instead offered a 21.5% increase over the same time period.

Kaiser spokesperson Kathleen Campini Chambers said union leadership had now accepted that lower offer.

UNAC/UHCP described the latest labor action as the "largest open-ended strike of registered nurses and health care professionals in United States history."