Turkish President Recep Tayyip Erdogan said he felt “serious sadness” at criticism against his country’s invasion of Syria from the Islamist regime in Iran on Tuesday, lamenting that President Hassan Rouhani did not “prevent” officials from condemning Erdogan.

Rouhani himself voiced disapproval of Erdogan’s “Operation Peace Spring” — a military invasion of Syrian Kurdistan (Rojava) to replace the indigenous Kurdish population there with some of the four million, mostly Arab Syrian refugees in Turkey — when it began this month. Erdogan did not address that criticism, instead insisting that Rouhani had a duty to keep Iranians from criticizing Turkey.

Erdogan made the comments before boarding a flight to Sochi, Russia, where he will meet with counterpart Vladimir Putin to discuss “Operation Peace Spring.”

Both Iran and Russia are close allies of Syrian dictator Bashar al-Assad, who loudly opposes any Turkish presence in his country. Erdogan has previously stated that the Turkish military’s only goal in Syria is to “end the rule of the tyrant Assad, who terrorizes with state terror.” He has since changed his tune, claiming that the Syrian Kurdish forces, the People’s Protection Units (YPG/YPJ), are a threat to the Turkish homeland. Ankara considers the YPG — U.S. allies who were indispensable to the fight against the Islamic State — indistinguishable from the Kurdistan Workers’ Party (PKK), a U.S.-designated Marxist terrorist organization.

“Operation Peace Spring” began after President Donald Trump ordered the removal of U.S. troops from Rojava, prompting Kurds to call the move a “betrayal.” Kurdish locals pelted withdrawing American troops with tomatoes and trash as they drove out of northern Syrian cities this week.

Assad repeated his demands that Turkish troops leave Syrian soil on Tuesday.

Asked about criticism from Iran, Erdogan said, “Some of the statements about the operation have caused serious sadness to me, of course these voices are outside the [Iranian] government and we will pursue this issue seriously.”

“Not [President] Rouhani himself but some of his close friends have issued oppositional statements … Mr. Rouhani should have prevented these statements,” he added. Erdogan said that Iran should not “forget” Turkey’s stance in support of Iran’s illegal nuclear weapons development.

“The approach that has been adopted today (by Turkey) and the secret agreements that have been made would not benefit the region,” Rouhani said on the first day of the Turkish invasion, “and we call on our friend and brother, Turkey, and its government, to be more careful and have more patience in such affairs and reconsider the path that has been chosen.”

Rudaw, a Kurdish news publication, added that Iranian Foreign Minister Mohammed Javad Zarif also criticized Erdogan, urging the Turkish president on Twitter to “end the incursion into Syria.” The Iranian Foreign Ministry also issued an official condemnation of the invasion through its regular press briefing on Monday.

Assad himself has aggressively condemned Turkey for invading Syria. In remarks paraphrased for his official media outlet, the Syrian Arab News Agency (SANA), Assad accused Turkey of “external greed” and making “criminal moves” to take over Syria.

“It is a blatant invasion and a clear aggression to which Syria has responded it in many places through striking its agents and terrorists, and Syria will respond and confront it with all its forms in any region of Syrian territory through all available legitimate means,” Assad reportedly said last week.

On Tuesday, Assad openly accused Erdogan not of seeking to eradicate the Kurds — who have accused Erdogan of “ethnic cleansing” and “genocide” — but of looting Syria’s natural resources.

“The Turkish president has stolen oil and wheat from Syria and also took factories away from Aleppo, and now [Tayyip] Erdogan wants to steal part of Syrian soil with its natural resources,” Russian news agency TASS quoted Assad as saying.

SANA, Assad’s news agency, also repeated accusations on Tuesday that Turkish soldiers are using banned chemical weapons against civilians in northern Syria. The Syrian Democratic Forces (SDF), an umbrella group largely including Kurdish fighters, claimed it had evidence of the use of phosphorus and unknown chemicals to burn children in Rojava last week. It also accused Erdogan of cooperating with the Islamic State to form an “Ottoman Khalifa [caliphate].”

A study published in February found evidence that Assad used illegal chemical weapons at least 300 times during the span of the eight-year-old Syrian Civil War.

Erdogan will arrive in Sochi to meet Assad’s and Rouhani’s main ally, Putin, on Tuesday. According to Kremlin spokesman Dmitry Peskov, the talks will be “long and complicated” and require patience, as Erdogan and Putin find themselves on opposite sides of the ongoing invasion.

“Russia wants to discuss the situation in northeastern Syria in order to better understand the events and get information about Turkey’s plans and compare it with general plans on promoting political settlement in Syria,” Peskov told reporters.

Erdogan told reporters he hoped for “very substantial opportunities” to come out of the meeting.

“We are hoping to increase our cooperation with Russia. Up to now, also with the contribution of Iran, we have been able to bring peace to the field, and we have worked hard to bring stability to Syria,” the Turkish president said.

Rudaw notes that the “peace” Erdogan has brought to Syria has killed at least 200 people and triggered a refugee wave of at least 300,000, most seeking to reach Erbil, the capital of Iraqi Kurdistan.

Erdogan noted that discussions with America have been productive, but French President Emmanuel Macron has tried to participate in negotiations without finding a constructive role to play. He accused Macron of meeting with “terrorists” (Kurds) and said he is looking to “make a place for himself in this agreement.”

Turkey and the SDF are currently abiding by a U.S.-brokered ceasefire set to end on Wednesday. The SDF has repeatedly accused Turkey of violating the ceasefire, including using chemical weapons during the ceasefire timeframe.

SDF spokesman Kino Gabriel told Rudaw the force wishes to abide by the ceasefire but will defend itself if Turkey violates the agreement.

“I don’t think we can be sure [of the ceasefire continuing]. This is related to the Turkish government and to what extent it adheres to it,” Gabriel said. “We could expect the continuation of military operations as Turkey, based on the statements of Turkish officials starting from the Turkish president to the minister of defense and others, speak of the necessity of completing military operations in Syria.”

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