The unprecedented 48-hour blockage was to implement a Sao Paulo state court order and was to take effect at 02: 00 GMT on Thursday, although it was not immediately clear if service providers would acquiesce to the order.

The court said WhatsApp had been asked several times to cooperate in a criminal investigation, but had repeatedly failed to comply.

A judge in Piaui state tried but failed earlier this year to block the app.

Authorities say they cannot disclose details of the criminal investigation because it is an ongoing case.