Kurdish militants claimed responsibility for Tuesday's bombing, the latest of a series of attacks on the Turkish military that has dashed hopes of a quick end to Turkey's decades-long separatist conflict with the guerrillas.

Kurdish separatists rebels have increased attacks on military targets after accusing Prime Minister Tayyip Erdogan's government of not delivering on promised reforms.

Erdogan, who faces a general election by July 2011, is under pressure to crack down on Kurdistan Workers Party (PKK) rebels, who have killed more than 50 soldiers over the last two months in some of the worst fighting in years in the mainly Kurdish southeast.

The Kurdistan Freedom Hawks, which have carried out bombings in the past, claimed responsibility for Tuesday's attack, the worst in Turkey's largest city in more than two years.

The group is believed to have links with the PKK, which launched an insurgency campaign in 1984 with the aim of creating an independent state for minority Kurds.

Anatolian did not provide details of Wednesday's detentions.

Firat, an agency close to Kurdish groups that frequently carries PKK statements, said Istanbul police detained more than 20 Kurds, most of them construction workers.

Erdogan's AK Party government has granted more political and cultural rights to minority Kurds in a bid to end the conflict, but the reforms were met with nationalist opposition and suffered a blow when the Constitutional Court last year banned a pro-Kurdish party in parliament for PKK links.

Anger over the deaths of soldiers in a country where all males have to serve in the military is so high that government officials have been attacked at funerals by angry relatives.

Opposition parties have accused the government of making political decisions that have weakened the struggle against the PKK and have increased calls to bring forward elections.

The military, also under public scrutiny after media reports of intelligence failures, is deploying troops and elite forces along the Iraqi border, where rebels are based.