President Joe Biden raised US “concerns” over <a href="https://www.thenationalnews.com/world/explained-turkey-s-controversial-s-400-missile-system-purchase-1.1129315" target="_blank">Turkish missile purchases from Russia</a> to President Recep Tayyip Erdogan at a Sunday morning meeting at which the two nations sought ways to avoid crises in the military relationship. The alliance has been tested recently by a threat to no longer recognise the US envoy and Turkey’s purchase of the Russian-made S-400 missile defence system. Mr Biden and Mr Erdogan sought to defuse the tension over the system and the subsequent breakdown of negotiations to buy F-35 fighter jets. According to official readouts the pair focused on their broader defence interests as Nato allies. A senior administration official said Mr Biden "made clear his desire to have constructive relations with Turkey and to find an effective way to manage our disagreements". “President Biden underscored his desire to maintain constructive relations, expand areas of cooperation, and manage our disagreements effectively,” a White House statement said. “He expressed appreciation for Turkey’s nearly two decades of contributions to the Nato mission in Afghanistan.” After talks that lasted for about an hour on the sidelines of the G20 summit, Mr Erdogan’s office said they agreed on a joint mechanism to deepen ties, though there were no details. The meeting was brought forward from a chat planned for the Cop26 summit in Glasgow this week. Mr Erdogan has lobbied for talks about the fate of the $1.4 billion Turkey paid for the F-35 fighter jets and invest in development of the warplane. Washington barred Ankara from purchasing and co-developing the jets after it bought Russian air-defence missiles that Nato allies fear could be used to collect intelligence on the plane’s stealth capabilities. Turkey has refused to jettison the missile defences as demanded by Washington. Mr Biden noted America’s concerns over the Russian S-400 system during the meeting, according to the White House statement. He “emphasised the importance of strong democratic institutions, respect for human rights, and the rule of law for peace and prosperity”, it said. “We’re planning to have a good conversation,” Mr Biden said as the two leaders stood together before their meeting. He did not answer questions about human rights and whether Turkey has grown too close to Russia. The pair also plan to discuss regional issues involving Syria and Libya, a senior US official said on Saturday. The official insisted on anonymity to discuss the conversation between Mr Biden and Mr Erdogan. Turkey’s role as a Nato ally has come under scrutiny in recent weeks. At a rally on October 23, Mr Erdogan said that 10 foreign ambassadors who called for the release of a jailed philanthropist should be declared persona non grata. The envoys, including US, French and German representatives, had previously issued a statement seeking to resolve the case of <a href="https://www.thenationalnews.com/opinion/comment/2021/10/10/turkish-prisoner-osman-kavalas-last-hope-lies-in-europe/" target="_blank">Osman Kavala</a>, a businessman and philanthropist held in prison since 2017 despite not having been convicted of a crime. Mr Erdogan did not follow through on the threat. But it reflected the rising tension with the US. “I cannot honestly say that there is a healthy process in Turkish-American relations,” state-run Anadolu news agency quoted Mr Erdogan as saying in September. Since Mr Biden became president, they have met only at a Nato summit in June where they discussed <a href="https://www.thenationalnews.com/world/turkey-to-run-kabul-international-airport-in-deal-with-nato-1.1233804" target="_blank">the possibility of Turkey securing and operating the Hamid Karzai International Airport in Kabul</a>. But those plans evaporated as the Taliban the swiftly took control of Afghanistan amid the US military departure. The Turkish president has said he’s open to buying a second Russian missile system, despite the controversy generated by his 2017 deal to acquire the Russian-made S-400 system. The US has denied making any financing offer over Turkey’s request to purchase F-16 warplanes, after Mr Erdogan said that may be a way of returning the $1.4bn. Turkey said it sent a formal request to the US on September 30 to purchase 40 new F-16 Block 70 aircraft and nearly 80 kits from Lockheed Martin Corp. to modernise its existing fighters. A Pentagon delegation visited Ankara on October 27 and discussed issues resulting from Turkey’s removal from the F-35 programme, which was finalised on September 23. A Pentagon statement called the discussions productive, and said a follow-up meeting would take place in Washington in the coming months. Mr Erdogan said that Turkey wasn’t given the option to buy American-made Patriot missiles. He also said the US hadn’t delivered F-35 stealth jets despite the $1.4bn payment. Turkey was kicked out of the F-35 programme with sanctions imposed on defence officials after it bought the Russian-made S-400 missile system. The US strongly objects to the use of Russian systems within Nato and says it poses a threat to the F-35s. Turkey maintains the S-400s could be used independently without being integrated into Nato systems, and therefore pose no risk. There are additional sources of strain for the two countries, including Turkey’s human rights record, US support for Syrian-Kurdish fighters whom Turkey considers terrorists, and the continued US residency of a Muslim cleric accused of plotting the failed coup attempt against Mr Erdogan’s government in 2016.