http://www.fco.gov.uk/en/travel-and-living-abroad/travel-advice-by-country/europe/turkey
Due to the high threat of terrorism we advise against all but essential travel to the provinces of Hakkari, Sirnak, Siirt and Tunceli. Visitors should remain vigilant when travelling in other provinces in south eastern Turkey.
? There is a high threat from terrorism in Turkey and a number of terrorist groups remain active in the country. Statements have been made in the press indicating that attacks could take place against tourists or places used by foreigners. Terrorist attacks have taken place in major cities and resorts against government, military and civilian targets. Improvised explosive devices (IEDs) have been placed in crowded areas, restaurants, refuge bins, outside banks and hotels and on dolmus mini-buses and trains. Terrorist attacks are regularly carried out against the security forces in the south east of the country by the separatist Kurdistan Workers Party (PKK). In the past, military personnel and German mountain climbers in the East of Turkey have been kidnapped. You should remain vigilant at all times.
? Al Qaeda and other networks inspired by religious extremism have specifically targeted western interests in Turkey and there remains a global risk of attack from such groups. See Safety and Security – Terrorism.
? Demonstrations occur regularly in major cities and have the potential to turn violent. Taksim Square and Istiklal Street in Istanbul are gathering points for those seeking to demonstrate. Police will take measures to control crowds using various means, which may include tear gas. While the focus of these may be in predominately Kurdish areas, it is possible that they may spread elsewhere.