BRASILIA, Brazil (AP) – Thousands of protesters marched to the presidential palace yesterday to demand the ouster of President Luiz Inacio Lula da Silva, whose administration has been rocked by a corruption scandal in the governing party.

Some 18,000 Brazilians gathered outside the Planalto Palace and chanted “Lula, get out,” a parody of Silva’s campaign slogan when he won the presidency in 2002, which called for “Lula there.”

Nearly 2,000 police officers, many on horseback, maintained order and kept protesters away from the palace. Silva had left Brasilia for a visit to northeastern Brazil.

The protest was much larger than a pro-Silva demonstration on Tuesday, when workers and students endorsed the president.

Yesterday’s march was organised by leftist parties and union groups unhappy with Silva’s conservative economic policy and the corruption scandal that has paralysed the government and the ruling Workers Party, or PT.

The scandal erupted in June when Rep. Roberto Jefferson, a former government ally, publicly accused the PT of paying monthly bribes to legislators to support government bills in Congress.

Silva was not personally accused of wrongdoing, but several top PT members were forced to step down – including Silva’s powerful chief of staff and longtime ally, Jose Dirceu. A congressional panel of inquiry is investigating the accusations.

On Wednesday, the party’s executive committee issued a formal apology to the country. “The acts that compromise us morally and politically with Brazilians were committed by leaders of the PT, without the knowledge of others,” the statement said.

The protest was the first anti-government demonstration since Silva took office on Jan1, 2003 as Brazil’s first elected leftist president.

“I voted for Lula, but he has betrayed the Brazilian people,” said Carlos Antonio de Souza, using Silva’s popular nickname. “Maybe he wasn’t personally involved, but he allowed it to happen by putting Jose Dirceu in charge.”