One of the sources was quoted as saying that finding traces of explosives is a rather difficult task.
"In the simplest case, you need three to seven days to completely explore the object," the source said.
The other source pointed out that it will take at least two weeks to wrap up a comprehensive test related to tracking traces of explosives.
He assured that the investigation is being conducted by the most experienced forensic experts using modern high-tech equipment.
The Russian Airbus A321 passenger plane crashed in Egypt's Sinai Peninsula on October 31 en route from Egypt's resort city of Sharm El-Sheikh to St. Petersburg.
All 224 people on board were killed. The crash became the biggest tragedy in the history of Russian and Soviet civil aviation.
