BRASILIA - Isolated shooting incidents in parts of Brazil marred local elections Sunday that were expected to hand big gains to the center-left ruling coalition of President Luiz Inacio Lula da Silva.

A 30-year-old unidentified man was shot and wounded by guards when he ignored warnings and tried to enter Lula's official residence in the capital Brasilia, officials said.

Lula was not there at the time, having gone to his southwestern home town of Sao Bernardo do Campo to vote.

The incidents were the most violent reported during a day of voting which was to elect mayors and councillors for Brazil's 5,563 towns and cities. Most polling stations closed at 2000 GMT, with only those in the westernmost part of the vast country staying open for another hour.

Initial results were expected later Sunday.

A second round of balloting was scheduled for October 26 in 79 cities if no candidates there win an absolute majority on Sunday. Casting ballots is compulsory for Brazil's 128 million registered voters.

Pre-election surveys and analysts suggested that Lula's leftwing Workers' Party -- known as PT in its initials in Portuguese -- and 13 allied groupings would sweep many of the main towns and cities.

The popularity of the president, who has a public approval rating as high as 80 percent, was expected to hand a big advantage to candidates running under his political umbrella.

The PT currently controls 13 of Brazil's 79 biggest urban centers, but will probably grab another 22 on Sunday, analyses by newspapers said.

The allied centrist Brazilian Democratic Movement Party (PMDB) will likely win another 17, while the opposition Social Democrats are expected to pocket around 20.

A political science professor, David Fleischer, said it was possible 600 PT mayors would be elected nationwide -- 50 percent more than in the last local elections in 2004.

The Folha de S. Paulo daily said the PT could win as many 700 municipalities.

"If things continue like this, the opposition is going to disappear," complained an opposition senator, Demostenes Torres, before the elections.

In Sao Paulo, Brazil's biggest city, the PT candidate Marta Suplicy -- Lula's former tourism minister -- benefited from campaigning with Lula as she vied to wrest the mayor's office from a rightwing incumbent. Nevertheless, that election was expected to be decided in the run-off.

Brazil's army was deployed to ensure safe voting in 460 towns, especially crime-ridden Rio, where 5,000 soldiers and 27,000 police officers were deployed.

A political analyst, Walder de Goes, said that if PT makes the big gains expected, Lula's efforts to be succeeded by his current chief of staff, Dilma Roussef, would be reinforced.

Under Brazil's constitution, Lula has to step down at the end of 2010 after having served the maximum two four-year terms.

The former trade unionist has won plaudits from both Brazil's poor and business elite for his centrist policies, which were accompanied by an economic boom driven by commodities exports.