ANKARA: Turkey began testing on Monday its Russian missile defence system, local media reported, despite repeated calls from the United States that it could lead to sanctions. Planes, including F-16 fighter jets, circled the Murted military base in Ankara province to test the newly acquired S-400 system and train Turkish operators, news agency DHA reported. Turkey’s acquisition of the S-400 in July was met with consternation by its Nato allies. The US argues there is a risk that sensitive technological information could be leaked if it is used alongside Western equipment such as the new F-35 jet. Turkey has ordered 100 F-35s and its defence industry was part of the supply chain for the new jet, until it was kicked off the programme due to the S-400 purchase. So far, the US has appeared reluctant to impose threatened sanctions on Turkey over the purchase, with officials saying it could be spared if it does not activate the S-400 system though this option has been rejected by Turkey. Ankara’s purchase of the S-400s has been a major factor souring relations with the United States, which says the system is not compatible with Nato defences and poses a threat to Lockheed Martin’s F-35 stealth fighter jets. The provincial governor’s office announced on Sunday that the Turkish Air Force F-16s and other aircraft will conduct low- and high-altitude flights over Ankara on Monday and Tuesday to test an air defence system project. Broadcaster CNN Turk and other media said specifically that the flights were to test the S-400 radar system. Ankara began receiving the S-400s last July but they are not yet operational. Dealers said the reports had a negative impact on the lira, which weakened to 5.7380 against the dollar from a close of 5.7140 on Friday. Tensions in US-Turkish relations played a major role in a near 30 percent slide in the lira’s value last year. As recently as last Thursday, a senior State Department official told reporters Turkey needed to “get rid of” the system. Those comments came after President Tayyip Erdogan met US President Donald Trump at the White House. Trump said their talks were “wonderful” but it was unclear if the two Nato allies made any breakthrough on the S-400 issue and Erdogan subsequently said US pressure to get rid of the S-400s was an infringement of sovereign rights. Washington has suspended Turkey from the F-35 programme, which it was a buyer and producer of, to punish it for the S-400 purchase. It has warned of possible US sanctions over the deal but has not yet imposed them. Trump has told Erdogan the United States is ready to sell Ankara US Patriot systems if it drops the Russian system. Earlier, Turkey ignored US warnings as it continued on Saturday to take delivery of Russia’s S-400 missile defence system near Ankara, a defence ministry statement indicated. “Delivery of S-400 Long Range Air and Missile Defence Systems resumed today,” the statement said. “The fourth Russian plane carrying S-400 parts landed at Murted Airport outside Ankara,” it added. The US fears that if Ankara integrates the S-400 into its defences, data about the US-built F-35 fighter jet could leak back to the Russians, and Washington has threatened to deny Turkey access to the stealth aircraft. The western defence alliance Nato, which counts Turkey as one of its members, is also “concerned about the potential consequences” of the S-400 purchase, an official said. Members of the US Congress have repeatedly voiced opposition to the move and threatened sanctions. “President Erdogan was given a very clear choice. Unfortunately, he has clearly made the wrong one,” said Eliot Engel and Michael McFaul, the top Democrat and Republican respectively on the House Foreign Affairs Committee. Ankara rejects the US warnings, and on Friday, Foreign Minister Mevlut Cavusoglu told reporters: “We say this each time. This is a done deal. The process continues. Russia flew a fresh shipment of advanced air defence equipment to Turkey on Saturday, the Turkish Defence Ministry said. The ministry said a fourth Russian cargo plane landed at the Murted air base near the Turkish capital Ankara, a day after three huge Russian air force AN-124 planes offloaded equipment at the base. Washington has tried for months to prevent the deal, arguing that the Russian S-400 air defence system is incompatible with Nato systems. It also says that if the S-400s are deployed near US F-35 jets, which Turkey is buying and helping to produce, they would undermine the stealth fighter planes’ defences. US officials had warned that Turkey would be thrown off the F-35 programme if it took delivery of the S-400s, and would also face sanctions under US legislation seeking to prevent countries from buying military equipment from Russia. Turkey says S-400 is a strategic defence requirement, above all to secure its southern borders with Syria and Iraq. It says that when it made the deal with Russia for the S-400s, the United States and Europe had not presented a viable alternative. The dispute between the countries with the two largest armies in Nato marks a deep division in the Western military alliance, which was forged after World War Two to counter Moscow’s military power. Reaction from Washington was limited on Friday, with acting Defence Secretary Mark Esper saying the US stance had not changed. Esper later spoke with Turkish counterpart Hulusi Akar. “Minister Akar told his US counterpart that Turkey remains under a serious air and missile threat and that purchase of S-400 defence systems was not an option but rather a necessity,” a Turkish Defence Ministry statement said. Investors in Turkey have been unsettled by the deal and the prospect of sanctions, a year after a dispute with Washington over the trial of a US pastor in Turkey contributed to a financial crisis which drove Turkey’s economy into recession. The Turkish lira TRYTOM=D3 weakened as much as 1.6 percent to 5.7780 against the dollar on Friday, before recovering somewhat. Russia’s TASS news agency quoted an unnamed military-diplomatic source on Friday as saying that a further delivery of 120 guided missiles would be carried out by ship at the end of the summer.