MOSCOW (Reuters) - Russia is improving defenses at its military bases in Syria and monitoring the situation in the Idlib de-escalation zone as Turkey has not yet set up observation posts in the area, Russian news agencies cited the defense ministry as saying on Wednesday.

The ministry also said that the Nusra Front militant group, which now fights under the banner of the Tahrir al-Sham alliance, had obtained portable missile systems, the agencies reported.

The group, linked to the former branch of al Qaeda in Syria, claimed responsibility on Saturday for shooting down a Russian Su-25 warplane with a shoulder launched anti-aircraft missile.