ASTANA (Reuters) - Russia, Turkey and Iran are close to finalizing an agreement on creating four de-escalation zones in Syria, a senior Russian negotiator said on Thursday. The three sides are discussing details of the agreement at meetings in Astana, the capital of Kazakhstan, Alexander Lavrentyev, who leads the Russian delegation, told reporters.  Our main task at this international meeting on Syria is to finalize and establish four de-escalation zones,  Lavrentyev said.  We are very close to reaching an agreement on creating these four zones.  The meetings, which also involve representatives of the Damascus government and some rebel factions, will continue on Friday. Lavrentyev said the agreement was likely to include provisions on the deployment of monitors - such as military police servicemen - in the four zones and, more specifically, on their borders. The previous round of Syrian peace talks in Astana in July ended with no agreement after Turkey raised objections. Russia and Iran, which back Syrian President Bashar al-Assad s government, and Turkey, which supports some of the rebels, have been holding talks in Kazakhstan since January and the meeting this week is their sixth. 