The site of a deadly blast outside a police station in an Istanbul suburb.

Turkish police on Tuesday said that the blast -- which killed at least one person -- was a suicide attack.

Istanbul's police chief spoke with reporters.

(SOUNDBITE) (Turkish) ISTANBUL POLICE CHIEF, HUSEYIN CAPKIN, SAYING:

"A suicide bomber blew himself up. The policeman working at the entrance was killed. Four security members including the station's police chief, a police captain and two police officers were wounded. The attacker blew himself up at the entrance of the police station."

The main domestic security threat in Turkey comes from the separatist Kurdistan Workers Party, or PKK, which is considered a 'terrorist' group by the United States, the European Union and Turkey.

But the PKK has focused its campaign on targets in the mainly Kurdish southeast.

Far-left groups and Islamist radicals have also carried out attacks in Istanbul in the past.