France says Turkey must avoid trading with sanctioned Russian firms

France's top diplomat on Monday raised the danger of Russia using Turkey to avoid Ukraine-related sanctions during a sensitive visit to Ankara that tried to navigate a range of prickly disputes.

Catherine Colonna met her Turkish counterpart Mevlut Cavusoglu before flying to Athens on Tuesday to address a new spike in tensions between the two NATO neighbours and historic foes.

Colonna made efforts at a joint media appearance with Cavusoglu to avoid a repeat of the public spat that developed during a visit by German Foreign Minister Annalena Baerbock to Ankara in July.

The German minister pressed Cavusoglu on Turkey's human rights record and openly sided with Greece in the regional dispute.

Colonna said she "questioned" Cavusoglu about the increasingly heated war of words between the two neighbours and urged him to avoid "any escalation, verbal or otherwise".

Turkish President Recep Tayyip Erdogan accused Athens over the weekend of "occupying" islands in the Aegean that are Greek but must remain free of troops under treaties signed after World War I.

"We have special ties with Greece," Colonna said. "But above all, we want the two neighbours and (NATO) allies to settle any difference they may have through dialogue."

Greece and Turkey have longstanding border disputes that have grown more urgent with the discovery of large natural gas deposits in the east Mediterranean.

French officials said ahead of the visit that Colonna was particularly focused on raising Russian sanctions-busting in Ankara.

The US Treasury sent an unusually blunt letter to Turkish businesses last month warning that they would be cut off from access to dollars should they trade with sanctioned Russian entities.

Erdogan and Russian President Vladimir Putin agreed to step up economic cooperation at a summit in Sochi on August 5.

Official data show the value of Turkish exports to Russia between May and July growing by nearly 50 percent from last year's figure.

Erdogan previously argued Ankara cannot join Western sanctions on Moscow because of Turkey's heavy dependence on Russian oil and natural gas imports.

Colonna said she would discuss the importance of foreign powers abiding by the sanctions during a private dinner with Cavusoglu later on Monday.

"We have the same goal," Colonna said.

"The sanctions policy we are pursuing has one objective, which is to limit the Russian war effort. The sanctions system deprives Russia's war effort. We will talk about that."

Cavusoglu did not react to the minister's comments about sanctions but said: "It is obvious that do not agree on everything with France, but it is not an obstacle to dialogue."