MOSCOW, April 28 (Xinhua) -- Russia, Iran and Turkey said Saturday that international meetings in the Astana format have made the most efficient contribution to the settlement of the Syrian crisis.

Russian Foreign Minister Sergei Lavrov and his Iranian counterpart Mohammad Javad Zarif and Turkish counterpart Mevlut Cavusoglu issued a joint statement after a trilateral meeting on Syria in Moscow.

They said the talks in the Kazakh capital helped combat terrorism, reduce the level of violence and create favorable conditions for a political settlement, including through facilitating the establishment of a broad intra-Syrian dialogue.

The three ministers agreed to hold the next round of international talks on Syria in Astana next month.

In parallel to the UN-sponsored Geneva process, eight rounds of Astana talks have been held since January 2017, with Russia, Turkey and Iran as the mediators.

The most significant outcome was the establishment of four de-escalation zones in Syria.

In Saturday's joint statement, the three countries reiterated their firm commitment to the sovereignty, independence, unity and territorial integrity of Syria.

The ministers confirmed their countries' determination to work for the final elimination of the Islamic State, the Nusra Front and other terrorist groups in Syria.

They also called on all armed opposition formations in Syria to completely and urgently dissociate themselves from the terrorist groups.

The three countries rejected all attempts to create new situations under the pretext of anti-terrorism and opposed separatist plans aimed at undermining the sovereignty and territorial integrity of Syria and the national security of neighboring countries.

The top diplomats strongly condemned the reported use of chemical weapons in Syria and demanded the Organization for the Prohibition of Chemical Weapons conduct a timely and professional investigation.