The Kremlin is trying to end more than a decade of hostility between the neighbours that began when Turkey backed rebel efforts to topple President Bashar al-Assad at the start of the Syrian civil war.

Turkey has since also launched a series of incursions into northern Syria, most of them targeting Kurdish forces it views as "terrorists".

Erdogan's foreign policy adviser Ibrahim Kalin said the Russian push for peace did not mean Turkey was abandoning the option of launching a new campaign that Ankara has been warning might happen for months.

"A ground operation is possible any time, depending on the level of threats we receive," Kalin told reporters.

"Turkey never targets the Syrian state or Syrian civilians."

His comments came two days after Assad said future talks with Ankara should aim for "the end of occupation" by Turkey of parts of Syria.

Turkey has military bases in northern Syria and also backs some local militias fighting against the regime.

Erdogan, who called Assad a "terrorist" in 2017, has opened up to the idea of meeting the Syrian leader ahead of Turkey's general election, now expected in May.

Syrian and Turkish defence chiefs held their first meeting since 2011 in Moscow in late December.

Kalin said the two sides will hold a "series of meetings" in preparation for a possible presidential summit.

He said a proposed meeting between the foreign ministers, expected to be held in Moscow, could take place in mid-February.

Kalin said that meeting might be preceded by another round of talks between the defense ministers.

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