SAN JUAN, Puerto Rico (AP) — Two powerful unions on the French Caribbean island of Martinique have joined protests against high living costs that recently have prompted France to send anti-riot police.

Traffic was paralyzed Tuesday after a transportation union ordered tractor-trailers to block main roads and public bus drivers to suspend service, according to the France Télévisions broadcaster.

Meanwhile, another union that represents health workers, local authorities and the private sector announced an indefinite strike starting Thursday. The union is demanding an increase in the minimum wage, retirement pensions and price controls on basic goods, among other things.

The protests began in early September and have turned violent, with at least six police officers and one civilian injured last week.

The anti-riot police from France, known as the Companies for Republican Security, arrived over the weekend at the request of Martinique’s government, which imposed a curfew and banned protests.