Tuesday morning’s bombing that killed at least 11 people including seven police officers in central Istanbul is the latest in a disturbing trend of attacks against security targets that is now focused squarely on Turkey’s major cities.
Although responsibility for the blast had yet to be claimed or attributed, police said that four people had been arrested on suspicion of involvement.
While visiting those injured at a local hospital, President Recep Tayyip Erdogan said: "We will continue to fight against these terrorists", a term authorities have repeatedly used to describe Kurdish militants operating in Turkey, Syria and northern Iraq.
Similar-type bombings that killed dozens of police officers and soldiers in Ankara last February and March have been claimed by a radical offshoot of the Kurdish PKK, the Kurdistan Freedom Falcons (Tak).
Tak is a little-known separatist group that had been largely dormant until peace talks between the Turkish authorities and PKK collapsed last year. It says it carried out the Ankara attacks in revenge for military operations conducted against Kurdish towns in southeast Turkey.
Airport bomb
The group also claimed responsibility for a bomb blast at Istanbul’s Sabiha Gokcen airport that killed one person in December.
For much of the past 12 months, clashes between the military and separatists have been confined to towns and rural areas of the predominantly Kurdish-populated southeast. Hundreds of civilians, mostly Kurds, and security personnel have died, and authorities say they have killed several thousand terrorists.
The majority of Turks back the military operations against the PKK, which is classified as a terrorist organisation by the European Union and the United States.
Media coverage in Turkey focuses largely on military operations and victories against the PKK, as well the deaths of security personnel and police, of whom over 500 have been killed since last July.
But now the resurgent war has gained a foothold in Turkey’s largest city, Istanbul, where about four million Kurds live.
In April, two Tak members were killed when security forces raided a home in Bolu province, between Istanbul and Ankara.
Planned attacks
Suicide belts, weapons and explosives were seized in two separate operations, suggesting the group has been preparing for attacks against either or both of Turkey’s largest cities.
Co-chair of the Kurdish-focused Peoples' Democratic Party, or HDP, Selahattin Demirtas has warned some Kurds in Istanbul are becoming increasingly ghettoised and isolated, and are refusing to travel outside of their neighbourhoods or interact with non-Kurds because of their opposition to the government's military actions.
“There are four million Kurds in Istanbul alone and even though there is no war here, society is divided.
“There are Kurds who now prefer to shop only in Kurdish stores. There are Kurdish slums developing,” he said.