Turkey's leader has unfinished business in Syria. What is he waiting for?

Syrian children stand near military vehicles during a joint Russian-Turkish patrol in the countryside, near the border with Turkey in Syria's northeastern Hasakah province on July 28.

A version of this story first appeared in CNN's Meanwhile in the Middle East newsletter, a three-times-a-week look inside the region's biggest stories. Sign up here.

Abu Dhabi, UAE (CNN)Turkish President Recep Tayyip Erdogan wants to launch yet another military incursion into northeast Syria.

Pledged almost two months ago yet awaiting what analysts say is probably a green light from Moscow, the operation raises questions about Turkey's ultimate plans for Syria.
Erdogan says he wants to initiate his fourth operation in the country's north since 2016, targeting a zone which includes the two key towns of Manbij and Tel Rifaat. The goal, according to the President, is to rid the area of fighters allied to the Kurdistan Workers' Party (PKK), a militant group that Turkey deems terrorist.
    "We are going into the new phase of our determination to form a 30-km (20-mile) deep safe zone along our southern border," Erdogan told lawmakers from his ruling AK Party in June. "We will clear Tal Rifaat and Manbij of terrorists, and we will do the same to other regions step-by-step."
      After a trilateral meeting between Erdogan, Russian President Vladimir Putin and Iranian President Ebrahim Raisi in Tehran yielded no evident developments last week, it seems that Turkey is still in talks with Moscow, hoping for Putin's blessing to put more boots on the ground.
      The Kremlin has thus far opposed the operation, saying it would not contribute to Syria's stability and security.
      Another attempt is expected next month in the Russian Black Sea resort of Sochi, where the Russian independent news agency Interfax reported Putin and Erdogan will be meeting.
        "Erdogan has been saying he would like to [launch] another cross-border [operation] into Syria and it's clear he wants to do this before the Turkish elections," said Asli Aydintasbas, senior fellow at the European Council on Foreign Relations.
        "But, as in the past cross border incursions, Turkey really needs a green light from Putin to do this," Aydintasbas told CNN.
        Erdogan's announcement in May came amid negotiations with the West over Sweden and Finland's accession to NATO, two Nordic countries which Turkey accused of harboring individuals with links to the PKK.
        While Turkey in June dropped its objections to membership for the Nordic states, it has recently renewed its threats, warning that it could veto their accession at any point if they do not comply with agreements ending support for the PKK and its affiliates.
        The PKK today remains Turkey's primary concern in Syria, and the main reason why it has continued to militarily cross into the Levantine state's territory.
        Designated as terrorists by Turkey, the US and the EU, the PKK have been embroiled in a long-running conflict with Turkey on each side of the border. In its decades of tension with the Kurdish fighters, Turkey has already launched three military operations against the PKK in Syria's north, the latest of which was in 2019.
        The aim has always been the same: to create a 30-kilometer deep, PKK-free "safe zone" in Syria that would allow more than two million Syrian refugees in Turkey to return home.
        Turkey says that its grand plan for the safe zone is not yet complete, and it is concerned about a "terrorism corridor" left after their previous operations, said Sinan Ulgen, a former Turkish diplomat and chairman of Istanbul-based think-tank EDAM.
        The targeted towns of Manbij and Tel Rifaat are technically under the control of the Kurdish-led Syrian Democratic Forces (SDF), analysts say.
        The SDF is backed by Washington. But its backbone is the Kurdish People's Protection Units (YPG), which Turkey considers a wing of the PKK.
        "Ankara sees no difference between the SDF and the PKK," said Ulgen.
        Washington has already warned Turkey against another incursion, with US Secretary of State Antony Blinken saying that "any escalation in northern Syria is something that we would oppose."
        Analysts say that Erdogan does take the US view into account, and that the Biden administration may take material action against Turkey in retaliation.
        "US criticism matters -- especially since it can spill over into other issues like congressional approval of F-16s," said Aydintasbas.
        Ankara in October requested to buy 40 Lockheed Martin Corp-made F-16 fighter jets from the US, as well as other military equipment. The deal is awaiting approval from the US Congress, which remains bitter over Turkey's previous purchase of Russian missile systems -- a move that triggered US sanctions.
        The complex web of control in Ankara's latest area of interest underscores the many agreements that will need to be settled between world powers before Turkey starts rolling more tanks on the ground.