FIFA on Monday condemned "all kinds of violence after a man was shot and injured by military police during an anti-World Cup demonstration Saturday in Sao Paulo.

"FIFA fully respects people's right to protest in a peaceful manner and as long as the rights of everybody are respected, but condemns any form of violence," a FIFA statement read after a 22-year-old man was left in a coma after being shot in the neck and groin.

Police said he was carrying an explosive device.

Having already warned Brazil it needs to speed up final preparations for the World Cup after accusing the host of starting work too late and leaving aside ongoing concerns over stadiums and other infrastructure issues such as transport, FIFA said it retained confidence in the "comprehensive security concept (put) in place by the Brazilian authorities for the Cup.

"The security concept has worked well during the FIFA Confederations Cup and is built on models used at previous FIFA World Cups," said world soccer's governing body.

Saturday had seen anti-World Cup groups call demonstrations in 36 cities against the multi-billion dollar cost of staging the tournament. Most were uneventful, but Sao Paulo saw acts of vandalism with a car set ablaze as well as a police vehicle and several office windows were smashed.

Local media reported 128 arrests following a turnout of about 2,500.

Although most people support the tournament as it returns to the home of the five-time champion for the first time in 64 years, Brazil is braced for social unrest of the kind which marred last year's Confederations Cup dress rehearsal.