The treasurer of Brazil's ruling Workers' says that all the donations made to his party during last year's political campaign were legal.

Joao Vaccari Thursday told a congressional committee investigating the kickback-corruption scheme at Brazil's state-owned oil company that the donations received by the party were registered at, and approve by, the Supreme Electoral Court.

According to federal prosecutors the scheme involved the alleged payment of at least $800 million in bribes and other funds by big construction and engineering firms in return for inflated contracts with Petrobras. Part of that that money allegedly went to the Workers Party.

Vaccari's testimony was briefly interrupted when a man released several brown mice in the hearing room. Security personnel quickly rounded them up and the session resumed.