(CNN) -- No evidence has surfaced of an explosion aboard a UPS cargo plane that crashed in Dubai last September, officials in the United Arab Emirates said Saturday.
But UAE authorities are seriously looking into a claim by a militant group that it was responsible for bringing the plane down.
Al Qaeda in the Arabian Peninsula, the Yemen-based arm of the al Qaeda terrorist network, claimed responsibility on Friday for the September 3 crash, which killed two pilots aboard, and last week's foiled plot to send parcel bombs to U.S. synagogues.
"The investigators did not report any explosion, only a fire in the cabin," Dahi Khalfan Tamim, Dubai's police chief, told CNN on Saturday. "Dubai police investigations revealed that an explosive parcel would have blown up the plane into pieces."
WAM, the United Arab Emirates News Agency, quotes the UAE's General Civil Aviation Authority on Saturday as saying that probe did not uncover evidence of a blast on board.
However, the authority said, officials are taking the claim seriously and it is under investigation.
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Investigators said earlier this month they had failed to turn up any evidence that terrorism was involved in that crash, which killed the two pilots aboard, according to a U.S. government official.
About 45 minutes after UPS Flight 6 departed Dubai International Airport for Cologne, Germany, the crew declared an emergency due to smoke in the cockpit. They asked to return to Dubai, but shortly before the plane could get to the airport, it crashed.
Officials in the United Arab Emirates have said -- and a U.S. official confirmed -- that the plane's cockpit voice recorder has been examined and nothing on it indicates an explosion. Explosions have distinctive sound signatures, and that would have been recorded on the device, the official said.
The UAE said it has "eliminated the possibility of an onboard explosion, following a detailed onsite investigation of the wreckage."
White House counterterrorism chief John Brennan said Sunday that the United States is "looking very carefully" at the September crash to see if it could be related to the recent terror threat involving cargo aircraft.
A U.S. counterterrorism official said Friday that while "there are very strong indications that AQAP was responsible for plotting last week's disrupted cargo plane plot ... we can't confirm at this point their claims about the early September incident."
The latest threat was revealed October 29 when authorities in the United Arab Emirates and Britain found two explosives-laden packages sent from Yemen that were addressed to synagogues in Chicago, Illinois.
The statement by AQAP said that since Western media did not link the September UPS plane crash to the group, "we decided not to announce it so we could carry on a similar operation."
"We did that this time using two devices, one of which was sent via the American UPS company and the other via the American FedEx company," the statement said.
The statement said its "developed bombs will allow us the opportunity to detonate them in the air or after their arrival to their ultimate destination and they are designed to pass through all detectors."
CNN's Rima Maktabi contributed to this report
