Three members of the terrorist group have been arrested in connection with the attack, which killed two, after the DHKP/C claimed responsibility for the attack on a website, Today's Zaman reported.
Erdogan complained about the criticism of the police's earlier investigation of the group, which led to 55 of its members being arrested in January.
"Lawyers and some top members of the group were captured. Yet there are people inside and outside [Turkey] who defend them," he said at a press conference. "One of them is the Republican People's Party. The fight against a terrorist organization in a country where the main opposition party is a supporter of that organization is not easy at all."
The DHKP/C has carried out nearly a dozen attacks in Turkey in the past seven months, Today's Zaman reported.