An explosion killed at least four people in Turkey's Istanbul Saturday, local media reported. The explosion comes days after a car bomb killed 37 people in Turkish capital Ankara. 

The blast occurred in Istanbul's Istiklal Street and is suspected to be a suicide bombing, according to the CNN Turk. As many as 20  people were injured in the blast, Istanbul Governor Vasip Åžahin said in a statement, according to Hurriyet Daily News.

This is the latest terror attack in recent months in Turkey, which is facing terror threats from Kurdish militants as well as the Islamic State group. The Kurdistan Freedom Hawks (TAK), a militant outfit affiliated with the outlawed Kurdistan Workers Party (PKK), claimed responsibility for the Ankara car bombing Sunday. 

Turkish jets have been conducting airstrikes on PKK bases in northern Iraq.

Earlier this week, the German embassy in Istanbul was closed following security threats.