Officials are combing through evidence connected with the car bomb found overnight in a parked SUV in New York's Times Square, Homeland Security Secretary Janet Napolitano said Sunday, calling the incident a possible terrorist attack. 

"It could be an act of terrorism," Napolitano told "Fox News Sunday." 

Though authorities have not publicly identified any suspects in the case, Napolitano said the New York Police Department, FBI and Department of Homeland Security are working together to find out who was behind it. 

"All the leads are being pursued," she said. "It's looking at the vehicle, it's tracing fingerprints, it's looking at video." Napolitano said nearby surveillance cameras could be a big help to investigators. 

Times Square was evacuated Saturday after police were alerted to the suspicious vehicle, which turned out to be carrying propane tanks and a clock suspected to be a timing device. They also removed gasoline and explosive powders from the vehicle. 

Authorities are looking into reports that a man was seen running from the SUV, an official told Fox News. 

Napolitano said Sunday that the bomb was "amateurish" and would not say whether it appeared to be the work of a domestic or foreign plot. 

"We're not ruling anything out at this point," she said. 

President Obama, who plans to fly into New Orleans Sunday to survey and assess the damage from the rapidly growing oil spill in the Gulf, has been monitoring the incident in New York. 

Both Obama and Napolitano were briefed Saturday night. White House spokesman Nick Shapiro said Obama ordered his homeland security and counterterrorism adviser, John Brennan, to advise New York officials that the federal government was prepared to provide support. 

According to a White House statement, the president was updated on the "excellent work" of the New York Police Department and "commended the quick action" taken by law enforcement.

Brennan and others will keep the president informed of progress made in the investigation, Shapiro said. 

The Associated Press contributed to this report.