Russian-flagged bulk carrier SV Nikolay is unloaded at Izmir port in Turkey June 25, 2022. REUTERS/Yoruk Isik/File PhotoBy Ebru Tuncay and Alexander CornwellISTANBUL (Reuters) -Abu Dhabi is set to buy a stake in a key Turkish port, according to four sources aware of the deal, in a further sign of a rapprochement between the once bitter geopolitical rivals. The port, owned by Turkey's sovereign wealth fund, is an important gateway that is in need of new investment.An official for the Turkey Wealth Fund declined to comment. AD Ports didn't immediately respond to a request for comment while ADQ, the emirate's sovereign wealth fund and majority owner of the ports group, wasn't available for comment. The Dubai state-owned port operating giant DP World bought a majority stake in a Turkish port earlier this year.