MINNEAPOLIS (AP) — The union representing 4,800 nurses at five Allina Health hospitals in the Twin Cities is calling on its members to authorize an indefinite strike.

The Minnesota Nurses Association made the request Tuesday, the day after contract talks between the union and Allina failed again to produce an agreement. The vote is scheduled for Aug. 18.

The nurses went on strike for seven days in June. Union spokesman Rick Fuentes tells Minnesota Public Radio News the decision to seek an open-ended strike it intended to put more pressure on Allina.

Allina says the company is "disappointed that the union's focusing on strikes rather than on solutions."

The cost of nurses' health insurance remains a major stumbling block.

The hospitals include Abbott Northwestern and Phillips Eye Institute in Minneapolis, United in St. Paul, Unity in Fridley and Mercy in Coon Rapids.