SAO PAULO: Brazilian riot police fired water cannon and tear gas to disperse anti-government protesters in central Sao Paulo on Friday, while in Congress opponents of President Dilma Rousseff started the clock ticking on impeachments sessions.

The anti-government protesters had blocked Sao Paulo’s central Avenue Paulista since Wednesday evening when demonstrations erupted against the appointment of former President Luiz Inacio Lula da Silva as a minister.

A federal judge issued an injunction to suspend his appointment on Thursday on the grounds that it was impeding the judicial process. The attorney-general said he would appeal this.

Authorities dispersed opposition demonstrators from Sao Paulo’s Avenue Paulista to avert possible clashes with a pro-government rally planned in the same area.

In Brasilia, where thousands of demonstrators have demanded Rousseff’s ouster over the last two days, police told protesters to stay away from the Congress building where a pro-government demonstration was planned.

In Congress’ lower house, opposition parties sped up the impeachment of Rousseff by holding a session on Friday, a day that lawmakers are normally away from Brasilia.

The president has 10 sessions of the house to present her defense and — even though the special impeachment committee did not meet on Friday — the clock started ticking. The impeachment case is centered on allegations that Rousseff broke budget rules to boost spending as she campaigned for re-election in 2014.

Antonio Imbassahy, the leader of the opposition Social Democratic Party of Brazil (PSDB) party in the lower house, lawmaker from Bahia, said the committee could present its finding by mid-April.

Lula’s appointment has been overshadowed by the release of taped telephone conversations between Rousseff and Lula that a crusading anti-corruption judge said showed them discussing how to interfere with his investigation into a massive corruption scheme centred on state oil company Petrobras.

The release of the recordings has inflamed tensions that were already running high between the judiciary and government.

“This was illegal,” Rousseff told a rally on Friday. “Only the Supreme Court has the authority to wire tap a president.”

In another tape made public on Friday, the president of the ruling Workers’ Party was heard asking Rousseff’s then-chief of staff Jaques Wagner to intervene after Sao Paulo prosecutors requested Lula’s arrest.

“Alert the president. There needs to be a State decision”, said Rui Falcao. “You have to do something, because the state judge may decide today.”

Wagner answered: “Ok, let me do something here.”

Lula and Rousseff both deny any wrongdoing.

The biggest counter-demos on Friday were expected in Sao Paulo, Rio de Janeiro and Brasilia, called by Rousseff’s Workers’ Party, the major CUT union and other groups.

Organizers said in a statement the demonstrations aimed to fend off a “coup” and to defend Rousseff’s social policies. The CUT in Sao Paulo vowed the rallies would be peaceful.

Brazil grabbed world headlines in 2013 when it was gripped by mass riots against corruption and increased transport costs.

Rousseff was scheduled to attend a ceremony in northeastern Brazil to unveil a new social housing project on Friday morning.

Brazil’s lower house of Congress launched a committee Thursday to consider impeaching Rousseff over corruption accusations.

She is accused of manipulating the government’s accounts to boost public spending during her 2014 re-election campaign.

The drive to impeach her was launched by the opposition in December but had been halted by the courts over procedural issues which were finally resolved late Wednesday.

“The putschists’ shouting won’t make me veer from my path or bring us to our knees,” said Rousseff as she was heckled at Lula’s swearing-in.

“If they violate the rights of the president, what will they do with those of the citizens? That is how coups start.”

Lula, who led Brazil from 2003 to 2011, is charged with accepting a luxury apartment and a country home as bribes from executives implicated in a multi-billion-dollar corruption scam at state oil company Petrobras.

Investigators say construction companies conspired with Petrobras executives to overbill the oil giant to the tune of $2 billion, paying huge bribes to politicians and parties along the way.

Lula denies involvement in the scandal.