Ankara is a player on all regional issues from the war in Ukraine, maritime corridors and NATO enlargement to incursions in Iraq or Syria and friction with neighbouring Greece.

And President Recep Tayyip Erdogan, who has been in power since 2003, can use them all to burnish his credentials as a strong leader in the runup to an uncertain re-election next year.

From one diplomatic file to another, Erdogan taps his finger on the table, insisting on his nation's security and interests.

US Secretary of State Antony Blinken has warned that a Turkish incursion into neighbouring northern Syria -- which Erdogan has brandished in order to "cleanse" the border of Kurdish fighters -- would undermine regional stability.

Erdogan does not appear ready to heed his warning.

The Turkish leader has raised threats in the midst of Sweden and Finland's bid to join the North Atlantic Treaty Organization, which he opposes on the grounds -- justifiable say analysts -- that the Nordic countries host "terrorists" from the PKK, the Kurdistan Workers Party and its allies.

The PKK allies are targeted by the military operation planned in Syria that aims to establish a 30-kilometre (18-mile) "security zone" along the border.

A Turkish offensive has already been under way since mid-April in northern Iraq for the same reasons.

- 'Diplomatic opportunity' -

Yektan Turkyilmaz, an analyst for Central European University in Vienna, said Erdogan sees an opening in the NATO membership debate.

"He's trying to transform the issue into a diplomatic opportunity," Turkyilmaz said.

"Sweden and Finland find themselves obliged to discuss Turkey's 'concerns.' Which in fact correspond to the right Turkey claims to treat 'terrorists' the way it wants," he said.

His assertiveness on this front also serves his internal political calculations ahead of the June 2023 presidential elections, according to Soner Cagaptay, a specialist on Turkey for the Washington Institute think tank.

"Of course Turkey had legitimate concerns regarding PKK and Swedish ties with the PKK and YPG," the Kurdish fighters in Syria, Cagaptay told AFP.

"Erdogan is preparing the public for a good battle with Europe that it will likely win, that Swedes will take steps to meet Turkey's concerns regarding the YPG and PKK," the analyst said.

"Even though they won't do everything that Turkey wants, Erdogan will claim it's a victory and frame it as a fight in which he has brought Europeans down to their knees," Cagaptay said.

"And in the end it will boost his strongman's image globally from which he will benefit domestically," he said.

Analysts also said Erdogan hopes to use the NATO membership issue to settle the row over F-16s, US fighter jets ordered and partially paid for before Washington suspended the deal after Ankara acquired a Russian S-400 missile defence system.

Turkey's latest friction with Greece serves to throw a wrench in a smooth running NATO because Erdogan accuses Athens of blocking the F-16s delivery.

- Irritant stance -

For Soner Cagaptay, it boils down to an Erdogan signal to US President Joe Biden:

"'Call me! We have a request to purchase the F-16s stuck in the US Senate... then I will be happy to lift my veto to Swedish and Finnish accession to NATO," he said.

Didier Billion, an analyst with Paris based Institute of International and Strategic Relations (IRIS), said Erdogan's "stance is certainly an irritant but his objections are often well founded".

"And beyond blackmail, in the end a compromise will be found," Billion said.

It is hard to sidestep the Turkish president, who has managed until now to maintain relations with Kyiv, armed with Turkish drones, without alienating Moscow, according to Elizabete Aunina, an analyst with the University of Amsterdam.

"It is notable that despite lack of notable mediation progress, Turkey still remains as the go-to trustable outsider considered good enough for mediation by both Ukraine and Russia," Aunina said.

Russian Foreign Minister Sergei Lavrov is due in Turkey Wednesday to discuss establishing "corridors" in the Black Sea to export Ukrainian wheat.

Ankara has proposed help and its Navy, and for now, Russia gives the impression it is considering the plan.

It will be Lavrov's second visit following talks in March in the southern city of Antalya, which remains the only face-to-face with his Ukrainian counterpart Dmytro Kuleba since the war began in late February.