Brazilian presidential candidate Eduardo Campos, a contender to unseat President Dilma Rousseff in October, died Wednesday when his jet crashed into a residential area, media network Globo said.
Campos, a socialist who has been running third in the polls, was on board a jet that crashed into a gym and houses in the city of Santos, breaking into pieces and sparking a large fire, Globo reported.
All seven people aboard died, the Brazilian air force told the online and television news network.
The plane was en route from Rio de Janeiro's Santos Dumont airport to Guaruja airport outside Sao Paulo when it hit bad weather, according to aviation authority spokesman Pedro Luis Farcic.
"As it was preparing to land, the plane fell due to bad weather. Air traffic control then lost contact with the aircraft," he said.
TV images showed the destroyed plane amid piles of burning rubble, with a large column of smoke rising from several houses.
Flames could be seen in the windows of some houses.
The air force said the plane was a private Cessna 560XL, a medium-sized jet.
There was no immediate confirmation that Campos was on board the plane from officials or from his party, the PSB.
Officials said multiple people had been killed in the crash, but were unable to give a death toll because the fire was hampering access to the area.
"There are fatalities but we still do not have a number confirmed," a Sao Paulo state police spokeswoman told AFP.
Santos firefighters said there were at least 10 people injured, according to Globo's online news portal G1.
Campos, the 49-year-old former governor of the northeastern state of Pernambuco, had eight percent support from likely voters according to a survey last month by polling firm Ibope ahead of the October 5 first-round election.
Rousseff, who is standing for a second four-year term, led the race with 38-percent support, while social democrat Aecio Neves had 22 percent, the poll found.
Media reports said Campos's running mate, ecologist Marina Silva, had not been on the plane.
Santos restaurant owner Thiago Fernandes said the impact had shattered the front windows at his business.
"I was working in the restaurant and there was a very loud boom, like nothing I had ever heard. All the front windows broke. Later they told us that an aircraft had fallen on the pool of a gymnasium a block away," he told Globo News TV.