Twin Cities janitors and security guards were back at the bargaining table Friday in a last-ditch effort to get new labor contracts before a strike deadline on Sunday.

The workers, part of the Service Employees International Union, are employed by third-party contractors to clean and monitor corporate offices throughout the area, including Target, Wells Fargo, U.S. Bank, Medtronic, Best Buy and Ecolab.

But they are prepared to call a strike late Sunday night if they don't reach a new labor agreement.

Officials from SEIU Local 26 said the new contracts the employers are proposing call for cutting 1,200 full-time janitorial positions, adding part-time shifts and ending health care benefits for many of the 6,000 workers covered under the old contracts. Security guards are also facing possible pay cuts and benefit cuts.

SEIU officials said many guards and janitors don't make enough to support themselves and so they want a raise, not cuts to hours and pay.

"The employers have offered nothing but cuts. They want to move us backwards, destroying and eliminating jobs for the middle class," said Paul Keith, who works at the Retek Building in downtown Minneapolis.

Janitorial contractors include ABM, Able Services, Marsden Building Maintenance, Harvard Maintenance, FBG Service Corp., Capital Maintenance, Triangle Services, Managed Services Inc. and Mid-City Cleaning. There are seven security contractors, including American Security, AlliedBarton, G4S Security and Securitas.

David Duddleston, the lawyer and spokesman representing seven security contractors, said talks with the union broke down at 4:30 p.m. Friday without a final agreement.

Duddleston said the union presented the contractors with a 107-page health care plan that it wants security employers to provide. Asked where the two sides go from here, Duddleston said that weeks ago contractors agreed to meet with the union again on March 13. Now, that's unlikely.

"We didn't get a deal, so we are going to strike," said Javier Morillo, president of SEIU Local 26, referring to the security guards. "We told them last week that Sunday was our deadline for getting a contract. We were planning to stay all weekend to get that contract. But they cut off negotiations after 4 p.m."

There are about 2,000 security workers who could strike starting early next week.

In contrast, talks with the cleaning employers were still going late Friday night, Morillo said. There are about 4,000 janitors who still hope to reach a contract this weekend, he said.

Yemi Rose, a spokesman for the contract cleaning contract firm ABM, also noted that janitor negotiations are ongoing.

In a recent letter to corporate customers, ABM said it is "committed to reaching a resolution [that is] in all parties' mutual interest." It said the company offered its janitors a 20 cent hourly raise and health insurance premium increases that range from 0 to 5 percent. ABM officials said the company picks up the tab for most health premiums.

As of late Friday, it appeared the janitors were prepared for an all-nighter.

"We have sleeping bags and pillows, and we are ready to talk through the night to make sure that hard work gets rewarded in Minnesota again," janitor Alfredo Estrada said. "We'll be here as late as it takes."

Supporters from various metro-area community and religious groups sent letters to corporate building owners this week urging their help in avoiding a crisis.

Corporations such as Target, Ecolab and others have largely declined to comment on the labor negotiations, referring questions to their janitorial and security contractors.

While those contractors care for corporate office buildings across the Twin Cities, those offices are not the only ones facing a possible strike order Sunday.

About 400 nonunion janitors who clean Twin Cities Target, Best Buy, Kmart, Sears, J.C. Penney and other stores said they are also prepared to walk off the job Sunday unless employers agree to labor talks and higher wages. Some make $8.50 an hour, have no benefits and say they have been threatened for trying to form a union.