A Russian jet that crashed in Egypt’s Sinai Peninsula may have been brought down by a bomb, the British government said Wednesday as it suspended flights to and from the region.

Downing Street said British aviation experts were traveling to Sharm el-Sheikh, where the flight that crashed Saturday originated, to assess security before U.K. flights to the popular tourist destination are allowed to resume.

“While the investigation is still ongoing, we cannot say categorically why the Russian jet crashed. But as more information has come to light, we have become concerned that the plane may well have been brought down by an explosive device,” Prime Minister David Cameron’s office said in a statement.

The crash in the Sinai killed all 224 people on the plane, a Metrojet Airbus A321.

A U.S. official told the Associated Press on Wednesday that early intelligence suggests a bomb brought down the Russian airliner. A day earlier, two U.S. officials told the news agency that satellite imagery detected heat around the jet just before it went down. However, officials are still investigating all possibilities for what may have caused the jet to crash.

Meanwhile, international air crash experts are making another attempt to evaluate information from the voice recorder on board the Russian plane, after damage to the device prevented an earlier try.

Germout Freitag, a spokesman for the German Federal Bureau of Aircraft Accident Investigation, said the plane’s flight data recorder was analyzed Tuesday but results were not yet reported. He said the plane's cockpit voice recorder could not be immediately evaluated because of damage but investigators were working on it again Wednesday.

Two Germans are helping with the investigation because the aircraft was manufactured in Germany, and French experts are involved because the plane was designed in France.

Meanwhile, the Sinai Province Group, an Egyptian affiliate of the Islamic State in Iraq and the Levant (ISIL), has allegedly reiterated its claim to have downed the plane.

In an audio recording circulated among the group’s supporters online Wednesday, a speaker said the crash coincided with the anniversary of the group's pledge of allegiance to ISIL. The dates of the crash and the pledge roughly coincide, according to the Islamic calendar.

Experts say the group lacks the sophisticated surface-to-air arms needed to shoot down a plane at cruising altitude. The speaker in the audio recording did not say how the jet was brought down.

The Associated Press could not independently verify the recording, but it resembled previous statements issued by the group. The U.S.-based SITE Intelligence Group, which monitors websites of armed groups, picked up the recording and circulated a translation.

Egyptian President Abdel Fattah El Sisi said an earlier ISIL claim was “propaganda” aimed at damaging Egypt’s image.

Al Jazeera and The Associated Press