SAN JUAN, (Reuters) - Tens of thousands of Puerto  Rican public workers protesting layoffs shut down the centre of  the capital San Juan yesterday in a one-day strike that  closed many government offices, businesses and schools.

Labour unions in the U.S. Caribbean island territory called  the 24-hour stoppage to protest the firing of thousands of  workers by the government, which is trying to shrink a $3.2  billion budget deficit.

While Governor Luis Fortuno insisted the layoffs were  essential to cut government spending and bolster the island’s  credit rating, around 50,000 protesters packed Roosevelt  Avenue, the main thoroughfare of the central Hato Rey financial  district in San Juan, witnesses said.

Most government offices and schools, and many businesses  remained closed yesterday during the strike protest, which  was also backed by religious and student organizations.

“The street will be our battleground. There will only be  peace when those that govern respect the will of the people,”  said Methodist Minister Juan Vera, who addressed the protesters  along with labor leaders and other personalities.

Puerto Rico’s unemployment rate was 15.8 percent in August,  higher than any U.S. state.

The island, which has a population of nearly 4 million and  is a manufacturing hub for petrochemical, pharmaceutical and  technology companies, as well as a major tourism destination,  has been in recession for more than three years.

Fortuno, who last month announced the firing of 17,000   public workers, appealed for calm but defended the government’s  strategy. Heavily indebted Puerto Rico is a leading issuer of  tax-free bonds in the United States.

“I will not allow our credit ratings to suffer any further  because of the effects it would have on the population,”  Fortuno told Reuters in an interview. “It is just unthinkable  …. We would be impaired from providing basic services.”

The government is hoping to avoid a downgrade of Puerto  Rico’s bond rating to junk, or non-investment, grade.

Bond rating agencies Moody’s and Standard & Poor’s rate  Puerto Rico a notch above junk level and Fortuno says any  downgrade would lead to even more job cuts.

San Juan’s international airport, as well as the port area,  operated normally yesterday. Buses stopped running but many  taxi cabs and the light rail system ran as normal.

Plaza Las Americas, the Caribbean’s largest mall located in  the Hato Rey district, shut its doors.