The bomb blast at 3:30pm (1330 GMT) shattered the windows of shops and offices in Istanbul's Bakirkoy district near the airport.
Tensions across the country are running especially high amid fighting between Turkish troops and PKK fighters in southeast Turkey, a mainly Kurdish area.
The clashes come as Turkey increases military pressure on its border with Iraq, fuelling speculation of operations in northern Iraq to attack PKK bases situated there.
In May, Turkish authorities blamed the PKK for a bomb attack in Ankara that killed eight people, although the group denied involvement.
Series of attacks
A series of violent PKK attacks on Turkish police and army troops has added pressure on the government to tackle the PKK.
On Saturday, three soldiers were killed in a roadside bomb blast in southeast Turkey blamed on Kuridsh separatists, days after a similar bomb killed four troops.
Kurdish fighters are also suspected of killing seven soldiers at a Turkish military outpost in southeast Turkey last week.
Ankara blames the PKK for the deaths of more than 30,000 people since it launched its armed campaign for an ethnic homeland in southeast Turkey in 1984.