Two airport employees have been arrested on suspicion of helping terrorists plant a bomb on board the Russian jet which crashed killing 224 people.
Egyptian authorities confirmed two workers at Sharm El-Sheikh airport are accused of aiding those responsible for the atrocity.
It comes as Russian investigators have confirmed the Metrojet flight WAS downed over the Sinai desert by a homemade bomb.
The device caused a blast equivalent to the force of 1.5kg of TNT.
Investigators said they found traces of explosives among the debris.
"Seventeen people are being held, two of them are suspected of helping whoever planted the bomb on the plane at Sharm El-Sheikh airport," an official said.
According to Reuters news agency, CCTV shows a baggage handler carrying suitcase from the main airport building to another man as he loaded luggage onto the doomed Metrojet flight before it left Sharm El-Sheikh.
Separately, investigators are also searching for two employees who are suspected of leaving a baggage-scanning machine unattended for a period of
time while passengers were boarding the doomed Russian plane.
The deadly crash was the result of a "terrorist act", Russia said, as President Putin vowed to hunt down those reponsible.(Image: Getty)
The Metrojet Airbus A321 crashed 23 minutes after taking off from the Sharm al-Sheikh tourist resort.
Islamic State militants fighting Egyptian security forces in Sinai said they brought it down.
According to local report, Federal Security Service director Aleksandr Bortnikov has told Russian President Vladimir Putin: "We can say that [the plane crash] was a terrorist act".
"During the flight, a homemade device with the power of 1.5kg of TNT was detonated.
"As a result, the plane fell apart in the air, which can be explained by thehuge scattering of the fuselage parts of the plane."
Putin has promised to find the culprits and has offered a $50million reward for information leading to the capture of those responsible.(Image: Getty)
He said: "It's not the first time Russia faces barbaric terrorist crimes."
"Killing our people at Sinai is among the most bloody crimes judging by the number of victims.
"And we won't wipe our tears away from our hearts and souls. It will remain with us forever.
"But it won't stop us from finding and punishing the criminals."
He vowed: "We must do it without time limitation.
"We must know each name. We will search for them everywhere, wherever they will hide. We will find them in any part of planet and punish them."(Image: Barcroft Media)
Islamic State (IS) has claimed responsibility for bringing the Russian plane down in written statements, as well as video and audio messages posted on the internet following the crash.
It said the attack was in retaliation for Russia's air campaign against IS - and other groups - in Syria, where Moscow wants to preserve the rule of President Bashar Assad.
The group warned Mr Putin that it would also target him "at home" but did not offer any details to back its claim.
While releasing specifics would add credibility, the group may be withholding either because its claim is false, or because doing so would undermine plans for similar attacks in the future - or because the aura of mystery might deepen its mystique among die-hard followers.
IS has also claimed responsibility for the attacks in Paris last Friday which killed 129 people and wounded 350 others.
The disaster has been described as another watershed moment for the aviation industry.
"What happened in Sharm al-Sheikh, and to a lesser extent with the... [Germanwings] aircraft, are game changers for our industry," Emirates Airlines President Tim Clark.
"They have to be addressed at industry level because no doubt the countries -- U.S., Europe -- I would think will make some fairly stringent, draconian demands on the way aviation works with security."
Foreign Secretary Philip Hammond also said the incident could lead to changes in flight security.