Istanbul circuit authorities defended their safety measures on Wednesday after a stray dog was run over on the track during a Turkish Grand Prix support race at the weekend. However, they could not guarantee that the problem would not happen again.Brazilian Bruno Senna, nephew of the late triple world champion Ayrton, hit and killed one of two dogs on the track during a GP2 support race before Sunday’s F1 GP at Istanbul Park.The 24-year-old was fortunate to escape injury and the incident prompted an enquiry by the governing International Automobile Federation (FIA), who raised the risk of possible sanctions.“This was a serious lapse in circuit security and safety,” an FIA spokesman said. “How could such a thing happen at an almost brand new Formula One track?”Istanbul Park Organizasyon AS, the circuit entity controlled by Formula One supremo Bernie Ecclestone, said they had done everything they could.Dog endemic“We take very seriously the matter of track safety, we took all possible measures to manage the problem and we cooperated with the FIA.” The authorities said the problem had nothing to do with the newness of the circuit and everything to do with location, with street dogs endemic in Istanbul and surrounding areas.“Unfortunately they are more noticeably prevalent at the circuit during the Grand Prix week, attracted we think by the various catering units that competitors bring with them,” they said.