The US military has shot down a drone belonging to Nato ally Turkey in northern Syria, as Ankara increases retaliation for a bombing in the Turkish capital claimed by Kurdish militants. Turkey denied ownership of the drone, but Pentagon spokesman Brig Gen Pat Ryder said the armed aircraft was Turkish and was posing a threat to US forces. Brig Gen Ryder said F-16s shot down the drone, which had been conducting air strikes, on Thursday morning after the US called Turkish military officials several times to warn them they were operating close to American ground troops. He said Defence Secretary Lloyd Austin spoke to Turkish Defence Minister Yasar Guler and “underscored the importance of close co-ordination between the United States and Turkey to prevent any risk to US forces”. “This is certainly a regrettable incident,” he said, noting the drone came within 500 metres of US forces within a restricted zone, but there was no indication the drone was taking aim at US troops. “US F-16 fighters subsequently shut down the [drone] in self-defence,” Brig Gen Ryder said. The shoot-down highlights the crowded battle space in north-eastern Syria, where competing interests increase the risk of mishaps. The US is supporting the Syrian Democratic Forces in their fight against ISIS, but Turkey views the Kurdish People's Protection Units (YPG) that dominate the SDF as an offshoot of the Kurdistan Workers' Party (PKK). The PKK has been locked in a decades-long conflict with Ankara over Kurdish autonomy. Washington sought to play down the incident's implications for its relations with Turkey at an awkward geopolitical moment. Mr Austin and Mr Guler committed “to one another that the US and Turkey will continue to closely communicate and co-ordinate”, Brig Gen Ryder said. “Turkey does remain a very important and valuable Nato ally and partner to the United States.” The incident occurred in Tal Baydar in north-eastern Syria, where US troops are assisting the SDF. Turkey is increasing its operations against <a href="https://www.thenationalnews.com/mena/2023/10/02/twenty-detained-after-kurdish-terror-attack-in-turkey/">PKK </a>operations after the attack on the Interior Ministry in Ankara on Sunday and has carried out strikes in areas of north-east Syria and northern Iraq. Kurdish militants launched a rocket attack on a Turkish military base in northern Syria on Thursday evening, wounding five police officers and three soldiers, Turkey's private DHA news agency reported. It said Turkish forces retaliated with rocket fire after the attack from the countryside in north-west Syria's Tal Rifaat region struck the base in the Dabiq area. The wounded personnel were taken to hospitals in Turkey, it said. Earlier on Thursday, Turkish strikes killed at least seven people, a Kurdish official said. Strikes on Hasakah province in Syria killed six workers at a brick factory and another worker in a separate factory, said SDF spokesman Farhad Shami. One of the Turkish strikes in the Kurdish-controlled region hit a car, killing two people, said the UK-based Syrian Observatory for Human Rights. Mr Shami said Turkish drones had also attacked military positions, civilian infrastructure and a military vehicle since the morning. He reported intensive overflights of areas controlled by the semi-autonomous Kurdish administration in north-eastern Syria “following Turkish threats”. A Turkish Defence Ministry official said on Thursday that a ground operation in Syria was one option Ankara could consider. “Our only goal is to eliminate the terrorist organisations that pose a threat to Turkey. A ground operation is one of the options to eliminate this threat, but it is not the only option for us,” the official said. The US-backed SDF – the Kurds' de facto army in the area – led the battle that dislodged ISIS fighters from their last holdouts in Syrian territory in 2019. Turkish Foreign Minister Hakan Fidan alleged the perpetrators of the bombing in Ankara <a href="https://www.thenationalnews.com/mena/2023/10/04/turkey-threatens-to-carry-out-more-air-strikes-in-iraq-and-syria-after-pkk-attack/" target="_blank">had been trained in Syria</a> and warned of reprisals against Kurdish fighters in north-eastern Syria. “It has become clear that the two terrorists came from Syria and were trained there,” Mr Fidan said. “From now on, all infrastructure, large facilities and energy facilities belonging to [armed Kurdish groups] in Iraq and Syria are legitimate targets for our security forces.” SDF commander Mazloum Abdi denied on Wednesday that the two Ankara assailants had “passed through our region”. “Turkey is looking for pretexts to legitimise its ongoing attacks on our region and to launch a new military aggression,” he said. “The threat to target the region's infrastructure, economic resources and populated cities is a war crime – a thing we have witnessed before.” The Democratic Union Party (PYD), whose armed wing led the fight against ISIS in northern Syria with US backing, said on Thursday that “the Turkish Foreign Minister's statements are tantamount to a declaration of war”. The PYD called on the international anti-ISIS coalition to “take a stand” and be on its side. Between 2016 and 2019, Turkey carried out three major operations in northern Syria against Kurdish forces.