How close are Turkey's Erdogan and Russia's Putin?

Here are some of the issues underpinning ties between Tayyip Erdogan and Vladimir Putin, who are set to meet on Wednesday in Russia on the sidelines of the summit of the BRICS grouping which NATO-member Turkey has voiced interest in joining:

WARY RESPECT

Relations between the long-serving Turkish and Russian presidents are sometimes tense, but they have both rebuffed U.S. influence and in differing ways have shaped military conflicts from the South Caucasus to Syria and North Africa.

Erdogan has said his relationship with Putin is based on a "joint understanding, mutual trust and respect". Putin has called Erdogan a "strong leader" and "reliable" partner while also saying he has not always found him easy to deal with. 

Their two countries, both with Black Sea coasts, have expanded cooperation on trade, tourism and energy since Russia's full-scale invasion of Ukraine, although Turkey has opposed Moscow's intervention and provided Kyiv with attack drones.

Military powerhouse Russia and regional power Turkey supported opposing sides in wars in Syria and Libya, and were not always on the same page in conflicts between Armenia and Azerbaijan over the Nagorno-Karabakh region. 

In Syria, Putin backed President Bashar al-Assad while Erdogan backed rebel fighters. To head off the threat of direct confrontation in early 2020, they struck one of a series of ceasefire deals after 34 Turkish soldiers were killed in an air strike in Idlib, where Russian jets were patrolling. 

In 2019, Turkey angered its NATO allies by buying Russian S-400 missiles, air defences that the Western defence alliance had warned were incompatible with its systems and a security risk.

In response, Washington imposed sanctions on Turkey's defence industries and ousted it from an F-35 fighter jet programme where it was a manufacturer and buyer. 

Ankara has not used the S-400 batteries since then, but says they are at the ready. 

ENERGY, ELECTIONS AND FOREIGN EXCHANGE RESERVES

When energy prices soared with Russia's invasion of Ukraine in early 2022, Turkey was vulnerable as an importer of nearly all its energy needs with an economy hit by a currency crash that fuelled inflation and depleted its foreign exchange reserves.

Russia, Turkey's largest gas supplier, threw Ankara a lifeline by allowing it to defer payment of gas imports until 2024, a move that sources said covered up to $4 billion in payments. 

The deal helped Turkish authorities maintain enough reserves to stabilise the lira until a May 2023 election that Erdogan narrowly won. Afterwards, the currency hit new lows.

Just before the vote, Erdogan's challenger accused Russia of interfering in Turkey's internal affairs and said his party had evidence - without revealing any - that it was behind the release of "deep-fake" online content.

Both the Kremlin and Erdogan dismissed the allegation and continued expanding energy cooperation, including at Turkey's Akkuyu nuclear power plant. Russia's nuclear energy agency Rosatom built the plant, the opening of which has been delayed after Germany withheld key parts.

In 2022, Putin proposed creating a Russian "gas hub" in Turkey that would help it reroute exports, after European countries curbed imports over the Ukraine war.

Turkey is negotiating the proposal and could leverage its extensive gas infrastructure to become an alternative supplier to countries such as Bulgaria, Hungary and Moldova, with which it signed separate deals in 2023.

SANCTIONS, TRADE AND OLIGARCHS

Turkey has opposed sanctions on Russia and opened its doors to Russian tourists and migrants, including oligarchs seeking safe havens for their yachts and investments. Russians are now the top foreign buyers of Turkish homes.

Bilateral trade has reached record levels, with Turkish exports to Russia up 17% to $11 billion in 2023, according to the Turkish Statistics Institute data.

Ankara has faced Western accusations that Russia is acquiring war-related goods such as chips and semiconductors via Turkey and the United States; European countries have imposed sanctions on several Turkish entities - and threatened more.

Ankara has said nothing that transits its territory is used in Russia's war in Ukraine.

Earlier this year, Turkish exporters to Russia faced more payments problems. The Kremlin said it was aware of Turkish banks tightening rules on Russian clients, and has been working with Turkey to find mutually acceptable solutions.

DIPLOMACY

Turkey has kept close ties with both Kyiv and Moscow, hosted talks between them in 2022 and positioned itself as a natural facilitator of future peace talks.

Putin and Erdogan have held several calls and a handful of meetings since the war began, contacts that provided the Russian president a platform alongside a NATO leader and NATO with a reliable line to Moscow.

Underscoring his balancing act with Russia and NATO, Erdogan has declared support for Ukraine joining the military alliance but delayed Sweden's membership bid.

Turkey's diplomacy and control of the straits connecting the Black Sea to world markets put it at the centre of an agreement between Russia, Ukraine and the United Nations on safe passage of Ukrainian agriculture exports and enhanced Russian exports.

The U.N. heralded Erdogan's role in co-brokering the 2022 Black Sea Grain Initiative, which it said helped relieve world hunger by freeing up exports of two top global producers.

Putin quit the deal in July 2023, despite pleas by Turkey to both sides, citing obstacles to Russian food and fertiliser exports and questions about the destinations of Ukrainian grain. 

In recent months, Turkey has also voiced a desire to join the BRICS group, which originally consisted of Brazil, Russia, India, China and South Africa, and has expanded to include Ethiopia, Iran, Egypt and the United Arab Emirates.

Ankara sees BRICS as an opportunity for more economic cooperation with member states, rather than an alternative to its Western ties and NATO membership.

Then U.S. Ambassador to Turkey Jeff Flake told Reuters in June that while he hoped Turkey would not join BRICS, such a move would not change its alignment with the West.