An act of terrorism could be the reason behind the crash of Kogalymavia's A321 passenger plane in Egypt’s Sinai, Russian Prime Minister Dmitry Medvedev said.

"A terrorist act, remains, of course, a possible reason for what happened," Medvedev told Rossiyskaya Gazeta newspaper.

Also Medvedev stated that resolving issues related to aviation security in Egypt may take quite a long time.

"I already said today, during a meeting with deputy prime ministers, that we should not indulge in illusions. These issues, related to security, cannot be solved very quickly. Therefore, it is likely that this will take a rather long time. The tourist flows will be formed based on this," Medvedev said.