The cause of the crash remains unknown, and Mr Calderon said his government would "carry out all necessary investigations to find out the causes of the tragedy".
At a news conference, Communications Minister Luis Tellez appeared to rule out any signs of foul play.
"So far, we have not detected any indications that suggest a hypothesis other than that it was an accident," he said.
Mr Mourino had been in charge of security during the government's violent battle with Mexico's powerful drug cartels, and his death is a big blow, says BBC Americas analyst Warren Bull.
About 3,000 people have been killed in drug-related violence since the start of the year, and the country's kidnapping rates are among the highest in the world.
The interior ministry officials had been returning to Mexico City from an event in the city of San Luis Potosi when the plane went down.
Mexico City Mayor Marcelo Ebrard said the crash had killed all those on board.
He added that more people might have died on the ground as a number of cars were destroyed when the plane crashed.
"It's likely that we will find other bodies in the vehicles," Mr Ebrard told Mexican television.
At least 40 people were admitted to hospital with injuries.
"The explosion was enormous," an eyewitness told AFP news agency.
"The flames reached higher than the buildings on La Reforma", the witness added, referring to the main street in the city's financial district.
Police and ambulances attended the crash scene as firemen battled to bring the blaze under control.
Correspondents say Mr Mourino had come under recent pressure over allegations he had acted improperly by signing government contracts on behalf of his family's car fuel business while in office. Mr Mourino had denied any wrongdoing.
Mr Santiago, who had previously been in charge of pursuing extraditions against drug smugglers, had reportedly been the target of at least one planned assassination attempt.
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