A small plane crashed in a wealthy Mexico City neighborhood on Tuesday, killing the nation's powerful interior secretary and at least seven others, and setting dozens of cars ablaze.

Juan Camilo Mourino was one of President Felipe Calderon's closest advisers and has been embroiled in scandal since taking office in the midst of Mexico's violent fight against drug cartels. He was in charge of the country's security.

"His death causes me enormous pain," Calderon told a news conference. "I ask all Mexicans that they don't allow any event, no matter how difficult or painful, to weaken them in the pursuit of a better Mexico."

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Presidential spokesman Max Cortazar said Mourino and a group of advisers were returning from an event in the city of San Luis Potosi when the plane went down. Officials say the crash appeared to be an accident.

The Learjet 24 set fire to about two dozen vehicles on a street in the posh Lomas de Chapultepec neighborhood in an area filled with tall office buildings.

Television footage showed rescue authorities fighting flames and keeping spectators away. Officials evacuated about 1,800 people from area offices.

Mayor Marcelo Ebrard said all those aboard the the plane were killed and that more people may have died on the ground.

"It's likely that we will find other bodies in the vehicles," Ebrard said in an interview with the Televisa news network.

A total of eight bodies were recovered. The jet seats eight, but it was unclear whether all the bodies were from the plane. At least 40 were injured, seven of them seriously.

Also aboard the plane was former assistant attorney general Jose Luis Santiago, who was previously in charge of pursuing extraditions against drug traffickers, and who had been the target of at least one planned assassination attempt in the past.

Mourino was also one of the most controversial officials in Calderon's cabinet, because of his family's involvement with private contracts to Mexico's state-owned oil company, precisely at a a time when Calderon sought to open up the legal framework for more such contracts.

Civil aviation officials were investigating the cause of the crash.