Eight members of the Progressive Student Labor Movement (PSLM) hand-delivered letters to administrators Friday, asking Harvard to cut its ties with Boston’s largest janitorial contractor until it provides better wages and health benefits to employees.

About 2,000 Boston janitors represented by Service Employees International Union (SEIU) Local 254 enter the fourth week of their strike today after negotiations with cleaning contractors failed last month.

PSLM members urged Harvard to cancel its deal with the janitorial contractor UNICCO, which employs about 5,500 of the 11,700 area janitors represented by SEIU.

The union is asking the contractors to extend health benefits to part-time workers and to increase numbers of full-time jobs. UNICCO has offered pay increases, but has said health care would not be feasible.

University spokesperson Joe Wrinn said Harvard would continue its agreement with UNICCO, through which it outsources about 400 janitors.

The current negotiations do not affect the janitors who work at Harvard. The union and PSLM successfully pushed for free health care for both in-house and outsourced Harvard janitors in contract negotiations last winter.

But PSLM member Jessica M. Marglin ’06, who helped draft the letter to Harvard, said contracting with the company gave Harvard’s “tacit approval” for restricting health insurance coverage for non-Harvard workers.

“UNICCO is by far the worst subcontratctor,” Marglin said. “Were Harvard to put pressure on them, it would send a big message.”

In the letter, delivered Friday afternoon to central administration offices at Mass. Hall, Harvard Corporation offices at Loeb House and the Office of Human Resources at the Holyoke Center, PSLM suggested Harvard end the contract with UNICCO and instead hire those janitors directly.

They also urged the University to require any privately-owned buildings where the school rents space to terminate UNICCO contracts.

“Should Harvard fail to meet these demands, its immoral position will surely reflect poorly on its image in the community,” the letter read.

The PSLM request follows an Oct. 10 promise by Acting Governor Jane Swift (R) to cancel the state’s cleaning contract with UNICCO in 60 days and only consider companies that provide greater access to health care in the new bid process.

At Mass. Hall, the first stop during PSLM’s delivery, four uniformed Harvard University Police Department (HUPD) officers as well as Associate Dean of the College David P. Illingworth ’71 were waiting outside and only one student was permitted inside to give the letter to a secretary.

One officer followed the students across the Yard to Loeb House, where a secretary also came outside to receive the letter. Three more officers met the students at the Holyoke Center and accompanied them until they left the building.

PSLM member Matthew R. Skomarovsky ’03 said the police presence was aimed at intimidating PSLM, which staged a three-week occupation of Mass. Hall in spring 2001 to protest for a living wage for Harvard workers.