NEW YORK (CBSNewYork) — The Russian government is suspending all flights to Egypt as it investigates whether a plane was brought down by a bomb, and the U.S. has also stepped up security at overseas airports.

As CBS2’s Matt Kozar reported, the U.S. Department of Homeland Security said it will expand its screening of everything going on aircrafts at overseas airports, including checked and carry-on luggage and catering, and other items loaded onto planes.

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They will also conduct an airport assessment of passenger and baggage screening procedures at about 10 airports across the Middle East and North Africa.

“When you talk about the shoe bomber, the underwear bomber, the printer cartridges — these all happened overseas with flights coming into the U.S.,” said former Transportation Security Administration assistant administrator Chad Wolf.

Russian officials said they have taken samples from the crash site in the Egyptian desert, which will be tested for traces of explosives.

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The analysis could confirm whether a bomb caused the Metrojet explosion this past Sunday, which killed 217 passengers and seven crewmembers.

U.S. satellite images showed a series of heat flashes at the time the plane went down, but it was unclear whether the flashes were from a bomb or mechanical failure.

U.S. and British intelligence have intercepted chatter from ISIS talking about the crash. If the downing of the Metrojet was an inside job, officials said authorities, along with airlines, must zero in on workers with security access.

“Once they hire these individuals, they need to keep continuing to vet them on a recurrent basis to make sure if they bad in the course of time as employees, we catch that before it’s too late,” said upstate U.S. Rep. John Katko (R-N.Y.)

The concern is whether ISIS can bribe an airport employee or infiltrate an airport with one of its operatives.

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CBS News has learned the Russians are asking for help from the FBI in their investigation – most likely for bomb analysis expertise.