Senior officials from Twitter held a third meeting with representatives from Turkey's information technologies authority in Istanbul on Monday to discuss various issues, including opening a Twitter office in Turkey.Tayfun Acarer, head of Turkish Information and Communications Technologies Authority, met with Sinead McSweeney, Twitter's director of public policy of Europe, Middle East and Africa, for the third time this year. Among the issues which were believed to be discussed during the meeting were the prospect of opening a Twitter office in Turkey and taxation concerns.Twitter's vice president and global public policy head, Colin Crowell, who was expected to lead the Twitter delegation, did not attend the meeting. Twitter does not have an office in Turkey despite Turkish authorities' requests for it to open a local branch. In April, Crowell met with representatives from Turkey's information technologies authority to discuss the possibility of opening an office in Turkey.Turkey and Twitter have been on unfriendly terms due to the popular microblogging site's shut-down during the March 31 local elections after the government ordered the removal of certain web links on the grounds that they violated privacy.