MOSCOW, May 6. /TASS/. Russian observers have registered 15 violations of the nationwide ceasefire in the past 24 hours, with most incidents registered in the Damascus region, the Russian center for reconciliation of warring sides in Syria said in a daily news bulletin on Saturday.

Russian officers "registered 15 ceasefire violations in the provinces of Damascus (9), Hama (3), Latakia (2) and Daraa (1)," the bulletin said.

The Turkish side reported eleven ceasefire violations, with four of them in the Damascus region.

"Looking into the violations, the Russian side established that it cannot confirm any of the eleven incidents," the document said.

The number of armed groups that had joined the cessation of hostilities agreement of February 27, 2016 has increased to 148 (against 143 on Friday). The number of settlements that joined the reconciliation process remained unchanged, standing at 1,479.

On May 4, Russia, Iran and Turkey agreed to set up four de-escalation zones in Syria. Under a memorandum signed at the talks in Astana, the four zones are Idlib province and some parts of neighboring provinces (Aleppo, Latakia and Hama), an area north of Homs, Damascus’s suburb Eastern Ghouta, and a number of provinces in southern Syria - Daraa and Al-Quneitra.

In those areas, combat operations, including flights by military aircraft, are outlawed as of May 6. The memorandum was concluded for six months with chances of automatic prolongation for another six months. Russia’s Defense Ministry said earlier that the fight against Islamic State and Jabhat al-Nusra terrorist groups (outlawed in Russia - TASS) would be continued inside and around those zones.

The Russian Defense Ministry declared the establishment of the reconciliation center on 23 February 2016. It is headquartered at the Hmeimim air base, Latakia province. The center was set up in line with agreements reached by Russia and the United States to facilitate the negotiations between the Syrian government and opposition and to organize humanitarian deliveries.