TORONTO -- A strike is under way at nine stores in southwestern Ontario owned by Loblaw Companies Ltd. (TSX:L).

Workers walked out at midnight at three Zehrs Great Foods outlets in Windsor and another in nearby Kingsville, and at two Real Canadian Superstore outlets in Windsor and at stores in Chatham, Leamingston and Sarnia.

The United Food and Commercial Workers union says 1,600 workers represented by Locals 175 and 633 are involved in the legal strike and that negotiations toward a new contract will resume today.

Loblaw says all nine stores will remain open, but with modified store hours (10 a.m. to 8 p.m.) and a reduction of some in-store services.

The company says another 60 stores represented by UFCW Local 1000A are scheduled to go on strike on Sunday in markets from London, Ont., to Ottawa.

The union has said the key issues in the dispute are wages, work schedules, benefits and limits on third party providers.