SAN FRANCISCO (KCBS) — The tentative deal reached between Twitter and the city of San Francisco is facing opposition from Local 1021 of the Service Employees International Union (SEIU).

On Wednesday, the South of Market-based micro-blogging site announced it would sign a six-year-deal to remain in the city if it were promised payroll tax breaks among other concessions. They’ve been looking at moving into the historic SF Mart building at Market and 9th Street; considered to be an economically challenged section of town.

READ MORE: UPDATE: Penngrove House Fire, Spot Fires Contained; Evacuations North of Petaluma Lifted

However, the city’s biggest public employee union, the SEIU, said the city can’t afford to offer Twitter such a tax break when jobs and basic services are being cut.

Negotiations have intensified within the last few months to keep Twitter within the city limits after the company threatened to relocate to a bigger office located in Brisbane on the Peninsula.

READ MORE: East Oakland Shooting Injures 1, Latest In Spate Of Gun Violence

San Francisco Board of Supervisor’s President David Chiu approves the proposed tax-policy changes that some argue would set a precedent that allows companies to make demands of the City without regard to the cost among other ramifications.

“The tax policy changes that we are proposing are very targeted for this neighborhood and will actually bring in millions of dollars for the city in short order,” Chiu said in defense of the deal.

Local 1021 were not available for comment on Saturday.

MORE NEWS: COVID: Contra Costa Health Officials Say 135 Hospitalized With Virus, Implore Unvaccinated To Get Shots

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services may have contributed to this report.)