A social network account of Russia's communications minister was temporarily blocked on Sunday in a cyber attack carried out by hackers presenting themselves as a Turkish activist group and parading images of a warplane and Turkish flags.Russia's ties with Turkey suffered a severe blow when a Turkish fighter shot down a Russian bomber near the Turkish-Syrian border in November, a move described by Russian President Vladimir Putin as "a stab in the back".Minister Nikolai Nikiforov's Instagram account was blocked by "The Börteçine Cyber Team" hackers, according to screenshots of the account, published by Russian and Turkish media and featuring Turkish flags, a portrait of Turkey's founding father Mustafa Kemal Atatürk, and a warplane.Instagram, where users post their pictures and videos, later restored Nikiforov's account and his profile photo, but the minister complained that the technical support team had not reacted to the incident for more than nine hours.The team, believed to be an ultra-nationalist group due to symbols, pictures and language used in hacked accounts, had earlier hacked the accounts of several Turkish politicians and journalists, including former president Abdullah Gül.Putin said he saw no way of improving ties with Turkey's leadership, while Moscow imposed economic sanctions on Ankara.Turkish media reports suggested in late December that Russian hackers could be behind recent cyber attacks on Turkish internet servers handling more than 300,000 websites.On December 25, Turkish banks reported sporadic disruption to credit card transactions, with local media repeating suggestions that the bombardment of public and financial websites could be coming from Russia, or staged by hacking group Anonymous.