In what respect exactly is Turkey accusing Russia of violating their agreement in Syria?

Question

Breaking news on the BBC is that Assad's army and Turkey's military have exchanged significant shelling in the past couple of days. It's also mentioned that:

In 2017, Turkey and Russia signed a "de-escalation" deal on Idlib, which came into force a year later.

The two sides agreed to jointly patrol the area to prevent clashes between the opposition and Syrian government troops.

Turkey, which has 12 military observation posts in the region, has accused Russia of violating the agreement, a claim Moscow denies.

In what respect exactly is Turkey accusing Russia of violating the agreement? Has Turkey released a longer explanation of what they accuse Russia of?

(N.B. after a bit of searching I was able to find the released text of the agreement but it's not very insightful as to what the claimed violations might have been, in regard to the recent events. Also, according to CNN the latest fighting marks the first deaths of Turkey's own military [as opposed to just its proxies] at the hands of Assad's army. According to the same source, Russia said that Turkey did not give advance warning of its troop movements this time, as [supposedly] previously agreed.)

Answer 1

Turkey accuses Russia of encroaching into territory they consider their own

Idea of agreement was pretty much straightforward: Russia and Turkey would force their respective proteges (government for Russia, and rebels for Turkey) to withdraw from designated demilitarized zone (this goes especially for heavier weapons) and establish ceasefire. Both Russia and Turkey would control their parts of DMZ. Eventually, talks would start about the future of the country.

Underneath the surface, agreement gave Turkey some kind of legalization for their encroachment on Syrian territory - they were not invited, had no mandate from UN, so technically they are aggressors. Syrian government actually considers them as such, but since Russia wants to avoid open war, they so far have put up with Turks. On the other hand, Turkey would certainly want to grab some of Syrian territory, but they do not dare to openly violate international borders, especially since all other powers in the region at least nominally agree to respect Syrian sovereignty. So they go for second best option - they want to rule part of Syria (Idlib mostly) with the help of their proxies, and to legalize that in a final peace agreement.

Unfortunately for the Turks, their proxies are not most reliably bunch (being a motley collection of various jihadist groups) . They could not agree on unified and realistic political platform, and begun shooting off various nebulous demands toward Syrian government. They also didn't fulfill their end of the bargain about DMZ and were often provoking SAA (regular Syrian army) with small scale attacks. Secretly, Russia and Syrian government were pleased with this, because it allowed them to make some ceasefire violations on their own, but on much greater scale.

Russia still doesn't want open war vs Turkey, but they have patiently waited until Turks soured their relations with US and the West, and for other hotspots to emerge around the world. Now, with Syria almost forgotten, they are launching limited but sharp offensives into rebel held territory, often bypassing Turkish observation post that remain behind new frontline. Syrian army was emboldened enough to open fire on mixed jihadi-Turkish convoy few days ago and kill some Turkish soldiers. So far, Turkey has not responded militarily, meaning that they too are not eager to start full war. It remains to be seen how long will current SAA offensive last . Usual pattern would be to move frontline few dozens of kilometers , then allow things to cool down, and repeat the same after some time. My guess is that without major geopolitical shifts, Syrian government would sometime in the future restore control in Idlib, wherever Turkey likes it or not .

Answer 2

I managed to find an actual statement of Turkish officials, snippets of which were quoted and paraphrased in the press, although apparently there were more:

Turkey President Recep Tayyip Erdogan has said that Ankara will not allow Syrian regime forces to gain ground in Idlib province, the last rebel-held area of Syria in comments published on Tuesday, a day after the Turkish soldiers died in regime fire.

"Syria is right now trying to buy time by driving those innocent and grieving people in Idlib toward our borders. We will not allow Syria the opportunity to gain ground there," Erdogan said in quotes published by the Hurriyet newspaper and broadcaster NTV.

"This is a clear violation of the Idlib agreement. There will of course be consequences for the regime," Erdogan said in the interview, which was given to Turkish journalists on his plane returning from a visit to Ukraine.

Erdogan had earlier criticised Russia, the key backer of President Bashar al-Assad's regime, for failing to enforce peace agreements in Idlib, but he toned down his rhetoric in the latest statement.

"We don't need to get into a serious conflict or a serious confrontation with Russia at this stage," he said. "As you know we have very serious initiatives with Russia."

So yeah, it was seemingly rather general criticism of "failing to enforce peace agreements" (in Turkey's view) by not reigning in Assad. A bit more searching found quotes from those prior statements, but they weren't anymore specific:

"Currently, Russia is not abiding by Astana or Sochi," NTV quoted Erdogan as saying.

Speaking to reporters on his flight back from Senegal, he said Turkey, which is building houses in northern Idlib to shelter civilians fleeing the bombing, has told Russia that it is running out patience.

"If we are loyal partners with Russia on this, they have to put forth their stance... Our wish is that Russia immediately makes the necessary warnings to the regime which it sees as a friend," he said.

"The Astana process has fallen into silence now. We need to look at what Turkey, Russia and Iran can do to revive the Astana process," he said.

Similar comments by Erdogan (might have actually been the same as the ones right above given the date, but with a different translation)

“Russia unfortunately isn’t loyal to Astana or Sochi,” he told journalists in reference to de-escalation agreements made in the two cities.

“There is no Astana process anymore. We are losing our patience in Idlib. [Russia] either stops the bombings in Idlib or we will take the necessary [steps].”

It's not clear to me that Russia actually signed up to stop Assad's troop from advancing in some document, so it was probably just how Erdogan interpreted their spirit...

Interestingly lower-level Turkish officials didn't express the same level of faith in Russia:

“We would always know that Russia wouldn’t uphold the ceasefires,” a Turkish official familiar with the issue told Middle East Eye.

“But at the least, Russia would stop the attacks for a week or two for the pretence. Now, they declare a ceasefire on Monday and continue their attacks on Wednesday.”

And not exactly about Idlib, but since Erdogan mentioned "Sochi" too, lower-level Turkish officials claim that the Kurdish SDF have not withdrawn and now blame Russia for this...

“They only replaced border guards with Assad's forces. That’s it,” a third Turkish official said. “Russians don’t even call on them to withdraw. They are in Kobane, in Manbij, they are still everywhere.”