AKIPRESS.COM - Brazilian President Dilma Rousseff has extended her lead ahead of Sunday's election and would win re-election in a likely second-round runoff, while her main challengers are almost tied for second place, polls showed on Thursday, reports Reuters.

Environmentalist Marina Silva has continued to slip and is now only 3 percentage points ahead of centrist candidate Aecio Neves, according to the Datafolha polling firm, a statistical tie because it is within the poll's margin of error.

Rousseff has advanced to within 3 percentage points of an outright victory in the first-round voting, or 47 percent, when spoilt and blank ballots are excluded, Datafolha said. If no candidate wins a majority, the election will be decided in a runoff between the two leading candidates on Oct. 26.

Rousseff's increased chances of winning a second term have weighed down Brazil's markets where investors are hoping for a change of government. Some blame Rousseff's interventionist policies for the stagnation of Latin America's largest economy.

Both the Datafolha poll and another by the Ibope research firm show Rousseff winning a runoff against Silva by 7 percentage points.