With a top Mexican business group calling for a tax protest, authorities are under growing pressure to stop blockades of streets and highways by demonstrating teachers.

Radical teacher unions have been blocking roads in southern Mexico for weeks, causing economic losses the business chamber estimates at almost $400 million. The CONCANACO chamber says members may file tax returns showing zero income if the situation continues.

On Wednesday, a federal court issued a rare injunction ordering Mexico City authorities to guarantee free movement on a street that runs in front of the federal Interior Department. The street has been blocked for weeks at a time by protest encampments.

The tribunal says city authorities have not ensured the right to protest has been exercised with due respect for the right of movement.