President Recep Tayyip Erdoğan will pay a one-day visit to Moscow tomorrow upon the invitation of Russian President Vladimir Putin.

The two leaders will discuss Turkey's latest military offensive and the violations committed by Syria's Bashar Assad regime in the de-escalation zone in Idlib.

The Turkish Directorate of Communications announced the president's visit in a written statement last Friday adding that apart from meeting Putin, Erdoğan will also attend the MAKS-2019 airshow and hold bilateral meetings.

In a recent phone call, Erdoğan and Putin discussed the latest developments in Syria, including the Syrian regime's increased offensive in the northwest that included attacks against a Turkish military convoy. According to a statement by the Turkish Presidency, during the conversation, Erdoğan told Putin that the Assad regime's attacks and violations in the de-escalation zone in Idlib were causing a major humanitarian crisis and posed a "very serious" threat to Turkey's national security.

"These attacks damage the efforts to regulate the Syrian conflict," the statement read.

A statement by the Kremlin, on the other hand, said both presidents agreed to "activate mutual efforts with the goal of liquidating the terrorist threat" in Idlib. Later on Friday, Erdoğan said he will visit Moscow on Tuesday to hold a meeting with Putin.

The visit takes place just weeks before Erdoğan is set to host Putin and Iranian counterpart Hassan Rouhani for the 14th Astana summit on Syria in Ankara on Sept. 16. The first meeting of the Astana process was held in Turkey in January 2017 to bring all warring parties in the Syrian conflict to the table to facilitate U.N.-sponsored peace talks in Geneva.

The recent developments in Idlib are the main reason that made it crucial for the leaders to meet to discuss the subject. The Assad regime has pushed deep into a small cluster of towns and their environs in the Hama countryside Friday morning, encircling opposition forces.

Sources on the ground had reported Wednesday that the regime forces had captured Sheikhoun, a small southern town in Khan, Idlib that is of strategic significance, following two days of intense fighting with the opposition.

According to the state-run Syrian news agency SANA, regime troops seized the villages of Latamneh, Latmeen, Kfar Zeita and Lahaya, as well as the village of Morek, where Turkey maintains an observation post.

Speaking to reporters Friday, Foreign Minister Mevlüt Çavuşoğlu said the observation point was not under threat and no force could take Turkish soldiers hostage. Turkish officials previously said the relocation or closure of the ninth observation post was "out of the question" and that it would be reinforced instead.

The latest Syrian regime offensive in the northwest has forced hundreds of thousands of people to flee toward the Turkish border.

Turkey and Russia agreed on last September in what is called the "Sochi deal" to turn Idlib into a de-escalation zone where acts of aggression are expressly prohibited. The Syrian regime and its allies, however, have consistently broken the terms of the cease-fire, launching frequent attacks inside the area.

The de-escalation zone is currently inhabited by 4 million civilians, including hundreds of thousands displaced by regime forces from cities and towns throughout the war-weary country. Yet, the number of people running from the attacks increases every day. The conflict, which entered its eighth year this year, has displaced more than 10 million people and killed hundreds of thousands of civilians, according to the U.N.