İstanbul Governor Vasip Şahin said in a statement after the incident that one of the attackers, a woman, was killed and explosives on her were seized, adding that the other was also captured.
The incident comes one day after two members of the extreme leftist Revolutionary People's Liberation Party-Front (DHKP-C) took prosecutor Mehmet Selim Kiraz, 46, hostage in his İstanbul office.
Kiraz had been leading an investigation into the death last March of Berkin Elvan, 15, who died nine months after falling into a coma after being hit by a police tear gas canister during anti-government protests in 2013. Kiraz and the two DHKP-C members died in a police rescue attempt.
The hostage-taking was in revenge for Elvan's death, the DHKP-C said on its website.