TEGUCIGALPA, Honduras (AP) — Masked men set fire to a pile of tires placed at the front door of the U.S. Embassy in the Honduran capital on Friday amid three weeks of street protests.

At least a half-dozen burning tires sent up a large plume of dark smoke at the embassy before Honduran soldiers moved in with fire extinguishers.

Thousands of teachers and medical workers have been protesting against recent presidential decrees that they fear could lead to massive layoffs in schools and hospitals.

On Thursday, at least 25 people were injured when police broke up a protest march; many of them suffered the effects of tear gas.

Protest leader Suyapa Figueroa, who also heads the country's health workers association, blamed the Friday fire on "infiltrators from this country's dictatorial government."

While a local television station had filmed footage of the men setting the fire, it wasn't clear who they were, nor why they weren't stopped by guards outside the embassy. A store was also attacked by masked looters.

The incident occurred a day after the U.S. Embassy urged protesters to avoid violence in the protests.