Russian Plane Crash: Sharm el-Sheikh Airport under New Scrutiny

US intelligence assessments suggest someone planted a bomb on the plane before takeoff, multiple US officials said Thursday, and that someone inside Sharm el-Sheikh airport could have helped, CNN reported.

The small airport in the popular Red Sea resort sees about 160 flights daily, and while there's a visible security presence, some who have traveled through there have said security appears lax.

British and Irish officials expressed concern about the safety of travelers, announcing Wednesday flights from Sharm el-Sheikh to their countries would be suspended.

Egyptian Foreign Minister Sameh Shoukry told CNN Egypt is providing sufficient security in the wake of the Russian airliner crash.

"We are cognizant of the interest and the concern, and have provided additional security arrangements in all of our airports for the protection of our tourists and also to indicate that we are not failing any efforts."

British experts arrived at the airport Wednesday to assess the security measures in place.

"The team noted that the Egyptian authorities had stepped up their efforts but that more remains to be done," according to a statement from British Prime Minister David Cameron's office.

Lax security?

If an explosive device brought down the plane, the United States does not believe it was designed to get past airport security procedures -- either passenger screening or other security measures --- in Egypt, a US official said.

Rather, it is believed whoever was behind it used a conventional bomb and took advantage of lax security or had someone complicit at the airport, the official said.

A British national security official said the British government is concerned about the airport because its experts have observed that security procedures are "poorly supervised" and "lack consistency."

The airport has a reputation for being understaffed at security checkpoints, CNN safety analyst David Soucie said, and a website with passenger comments about their airport experience had complaints about security employees who stole items or acted rudely.

But Soucie also noted that the airport has stricter-than-average security checks for passengers, including putting all baggage through a barometric pressure device that would activate a bomb with altitude-sensitive detonators.

If a bombing were an inside job, however, it wouldn't have been stopped by security measures the average airline passenger goes through, he said.

Security lapse in May

Like most airports in the world, Sharm el-Sheikh Airport doesn't do a very good job of controlling access outside the terminals, Soucie said.

In May, a mentally disturbed man slipped through a hole in a wall and tampered with a plane, the Cairo Post reported, citing Egyptian newspaper Youm7.

The man approached a plane sitting on the runway and tried to open a door to the aircraft, the article said. He was arrested after moving a block in front of the plane's wheel, the article said.

Operating in a tense region

Some airlines already avoid flying over the Sinai region, where ISIL-affiliated militants have been battling Egyptian security forces for the past few years.

Air France, KLM, Lufthansa, Emirates, Qatar Airways, Air Arabia, Etihad and flydubai have recently opted to reroute their flights to circumvent the area.

The European Aviation Safety Agency issued guidance for the region a year ago, when it warned civilian aircraft operators about a "significant risk" because of "ongoing insurgent activity" in North Sinai, and told airlines to not fly below 26,000 feet.

The Federal Aviation Administration, which controls US airlines, issued similar guidance in March.