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The Associated Press
In this photo released by the Syrian official news agency SANA, Syrian president Bashar Assad, right, meets with Alaeddin Boroujaerdi, who leads the foreign policy and national security portfolios at Iran's top Shura Council, left, at the Syrian presidential palace, in Damascus, Syria, Wednesday, Jan. 4, 2017. Assad received Boroujaerdi and called the friendly state "partners in the victory that was achieved in Aleppo," referring to the city that pro-government forces recently wrestled back from rebels, with Iranian help. (SANA via AP)

BEIRUT — Turkey warned on Wednesday that repeated cease-fire violations by Syrian government forces threaten to derail peace talks scheduled for later this month.

Foreign Minister Mevlut Cavusoglu said the talks in Kazakhstan, due Jan. 23, are to be preceded by preparatory meetings between Turkish and Russian experts in Turkey.

The Syrian government troops and allied militias have pressed an offensive to take the Barada Valley near Damascus from the rebels — despite a cease-fire agreement signed shortly before New Year's. The government says the region was never included in the agreement. Details of the deal have not been publicized.

Amid the government offensive, the rebels have retaliated with shelling and raids on government-held areas in other parts of the country. The rebels also accuse the government of carrying out air raids in the rebel-held province of Idlib, where hundreds of thousands of civilians have sought refuge from the civil war, now in its sixth year.

Cavusoglu called on Iran, a key ally of Syrian President Bashar Assad and one of the guarantors of the truce agreement, to address the violations by pro-government forces. Turkey supports the Syrian opposition.

Meanwhile, Assad received a top Iranian official in Damascus and called the Shiite country his "partners in the victory that was achieved in Aleppo," referring the city pro-government forces recently wrestled back from rebels, with Iranian help.

The Iranian official, Alaeddin Boroujaerdi, in charge of foreign policy and national security portfolios in Iran's Shura Council," called the capture of Aleppo a "big step toward restoring security and stability nationwide."

The cease-fire declared last week between the government and the opposition was supposed to prepare the way for the talks in the Kazakh capital of Astana, in what would be the first substantial diplomatic movement toward ending Syria's conflict in nearly a year. Russia, Turkey, and Iran had agreed to broker those talks. Russia is also a key ally of Assad.

Cavusoglu warned in remarks made to Turkey's state-run Anadolu news agency that the Astana process "might fail if we cannot stop the escalating violations."

The cease-fire agreement has restored some calm, according to figures from the Britain-based Syrian Observatory for Human Rights. The group, which tracks the conflict, reported that 11 civilians were killed from fighting in areas contested by the government and rebels since the truce started five days ago — a dramatic decrease compared to earlier fatality rates.

The Observatory also said that 32 civilians were killed in fighting over areas controlled by the Islamic State group, areas that are not covered by the truce.

Cavusoglu said he had received assurances from Russia that the Kurdish Syrian PYD party would not be invited to Astana. Turkey considers the party an extension of its own, outlawed Kurdish insurgency and classifies it as a terror organization.

The PYD controls most of the Syrian-Turkish frontier. Its armed wing enjoys the backing of the U.S. military, and is the most effective ground force battling Islamic State militants in Syria.