Egypt says it has not yet found any sign of terrorism in the deadly Oct. 31 crash of a Russian passenger jet in the Sinai desert, a preliminary finding that conflicts with Russian, U.S. and British statements that they believed a bomb on the aircraft probably was to blame.

The vaguely worded Egyptian statement released Monday reflected the deep reluctance among government authorities to point to the possibility of a bomb, and the implication of lax security at the Sharm el-Sheikh airport, where the Metrojet plane took off.

The Airbus A321-200 broke apart 23 minutes after departing the Red Sea resort for St. Petersburg, killing all 224 people aboard. The crash led Russia to halt all flights to and from Egypt, while Britain suspended flights to and from the resort. The actions inflicted a heavy blow to Egypt's vital tourism industry.

Several officials involved in Egypt's investigation told The Associated Press that security gaps at the Sharm el-Sheikh airport were making finding a culprit more difficult, including poor video surveillance and the number of people who could enter the facility with only limited searches.

Soon after the crash, the U.S. and Britain said the plane probably was brought down by a bomb, in part citing chatter among militants in Sinai. On Nov. 17, Moscow also announced a bomb was to blame, saying its tests had found the equivalent of one kilogram of TNT went off aboard the Airbus, causing it to break apart in the air.

In response, Egyptian Prime Minister Sherif Ismail said only that his country would "bear in mind" the Russian conclusion.

Debris from crashed Russian jet lies on the sand at the site of the crash, as seen on Oct. 31 in Sinai, Egypt. (EPA)

A local affiliate of the Islamic State group claimed responsibility and released an online photo of what it said was the bomb used to bring the plane down — a soft-drink can packed with explosives with wires that appeared to be a kind of detonator.

The head of Egypt's main investigation, run by the Civil Aviation Ministry, said its inquiry so far has found no evidence of any "illegal or terrorist act." Its preliminary report has been given to other countries involved, and it is continuing its work, said chief investigator Ayman el-Muqadam.

He also complained that the countries contending a bomb was to blame have not given his investigators "any information indicating unlawful interference" with the plane.

Two separate Egyptian inquiries

The ministry-led investigation, in which Russia and several other countries are taking part, has so far focused on technical aspects of the plane, including analyzing cockpit voice and flight data recorders. The prosecutor's office has a separate inquiry involving the Interior Ministry, which is supposed to determine whether a criminal act took place.

The head of the prosecution-led investigation, Emad el-Dahshan, told AP that "we have no suspects." He said video surveillance of the airport showed nothing.

But two officials involved in the investigations said Egyptian police had run their own tests of wreckage that had come up positive for traces of explosives, and that the results were received even before Ismail made his comments. The officials spoke on condition of anonymity because they were not authorized to talk about the investigation.

The results of the tests have not been made public. Police spokesman Abu Bakr Abdel-Karim said he had no information on the test. Asked about the test, el-Dahshan referred the AP to another prosecutor, who did not answer calls for comment. The Civil Aviation Ministry could not be reached for comment, but a member of its investigation said his team had not been informed of any wreckage test results.

Three officials involved in the investigations said the authorities' reluctance to acknowledge a bomb could have been smuggled into the airport stems from their refusal to admit to a security failure and it is affecting the seriousness of the probe.

"They are in denial," said one of the officials, who spoke on condition of anonymity because they were not authorized to talk to the media.

Questions about lack of video surveillance

Among the security gaps is insufficient video surveillance of the Sharm el-Sheikh airport. The area where planes are parked for loading, refuelling and boarding is about 50 square kilometres and it is covered by fewer than 20 security cameras, the three officials said. Airport security officials have complained before about the lack of cameras and the poor resolution of those in place, they said.

The bags for the Metrojet flight remained out of camera sight for 50 minutes after leaving the sorting area, two of the officials said. Only one camera managed to capture the plane from a distance. It appears small and grainy in a corner of the video, but it's difficult to see clearly which of the almost 40 ground service employees went near it, they said.

Also, they said, many people working at the airport, including most of the police and local hotel catering employees delivering food for the planes, are not properly searched when entering. Nearly two-thirds of the food trolleys were loaded onto the Metrojet flight without being X-rayed, the officials said.

One of the officials involved in the investigation said 35 airport employees entered the facility on Oct. 31 with lunch bags that were not X-rayed.

"And these are just the violations of that day. It could have been smuggled before the 31st. How far back should we look?" said one of the officials.

Authorities "don't want to admit that there are security shortcomings that can allow for that to happen," he said. Security officials believe airport police who often accept bribes to smuggle in various illegal items "would not have the heart" to smuggle a bomb, he added.

Airport employees with access to the Metrojet plane have been interviewed multiple times by investigators, asked mainly about their movements Oct. 31 and whether they saw anything suspicious, the officials said. No one has been put under official investigation.

Passengers check the departure information board at Sharm el-Sheikh Airport in south Sinai, Egypt. (Ahmed Abd El-Latif/The Associated Press)

Almost no voices in the mostly pro-government Egyptian media have considered a bomb a possibility. Some on TV and in newspapers have said that if it was a bomb, it was probably smuggled aboard during a stopover in Turkey. The aircraft, however, made no stops in Turkey, according to el-Muqadam, the plane's itinerary and officials from Russia, Metrojet and its operator in Sharm el-Sheikh.

The theory seems rooted in politics: Egypt's relations with Turkey have been strained ever since the military's 2013 ouster of Islamist President Mohammed Morsi, whose Muslim Brotherhood is supported by Ankara.

Nevertheless, el-Dahshan, the head of the prosecution investigation, cited the theory as a possibility. "Turkey is certainly one of the possibilities we are considering," he said. "It is our job to see where that plane came from."

After the 1999 crash of EgyptAir Flight 1990 into the Atlantic Ocean near the Massachusetts island of Nantucket that killed all 217 people aboard, U.S. investigators filed a final report that concluded its co-pilot switched off the autopilot and pointed the Boeing 767 downward. But Egyptian officials rejected the notion of suicide altogether, insisting some mechanical reason caused the crash.

At the time, Egyptian authorities accused the Americans of failing to share information with them, similar to the complaints they are making now.