Brazilian police are carrying out the biggest security operation yet for a football match here, as Brazil plays Spain in the final of the Confederations Cup.

Authorities say 6,000 regular police will patrol near the Maracana football stadium along with nearly 500 investigative officers. About 73,000 fans are expected to attend the match.

Elite federal troops are present, but officials won't say how many. Local media put the number at a few thousand.

The show of force comes after two weeks of anti-government protest across Brazil.

Much of the protesters' ire has been aimed at the billions of dollars Brazil has spent hosting upcoming events such as the World Cup and Olympics.

However, just a few hundred protesters had gathered near the stadium in Rio several hours before the match.