CAIRO (Reuters) - Egyptian authorities have detained two employees of Sharm al-Sheikh airport in connection with the downing of a Russian jet on Oct. 31, killing all 224 people on board, two security officials said on Tuesday.

"Seventeen people are being held, two of them are suspected of helping whoever planted the bomb on the plane at Sharm al-Sheikh airport," one of the officials said.

Russia's FSB security service said on Tuesday it was certain a bomb brought down the plane, joining Britain and the United States in reaching that conclusion. Egypt has not yet confirmed a bomb downed the jet.

(Reporting by Cairo bureau; writing by Luke Baker)