Last Sunday's attacks were the bloodiest in Turkey since 2003
A number of people have been arrested over last Sunday's double bombings in Istanbul that killed 17 people, Turkey's interior minister says.
Besir Atalay blamed Kurdish separatist rebels for the blasts, and said most of those involved had been detained.
Although he did not specify how many people had been arrested, a prosecutor said separately that eight suspects should be charged with PKK membership.
The Kurdistan Workers' Party (PKK) has denied any role in the attacks.
But security services say the blasts bore the hallmarks of the Kurdish rebels.
The unnamed prosecutor asked an Istanbul court to charge eight suspects arrested in connection with the bombings of belonging to the PKK, and release the remaining two, Turkey's semi-official Anatolia news agency reported.
'No room for doubt'
Speaking next to a display of weapons, computer hard drives and other items collected from the homes of the suspects, Mr Atalay cited "strong evidence" against them.
"Our judgement is that this merciless attack was the work of the bloody separatist group," he said.
"Those who helped, those who gave shelter and those who took part in the attack have been caught."
"I'm pleased to tell you that the entire plot is illuminated; a big part of the perpetrators were arrested in the light of strong evidence that doesn't leave any room for doubt."
The PKK is considered a terrorist organisation by the US and EU, as well as Turkey.
Children among dead
Turkish Prime Minister Recep Tayyip Erdogan had earlier implied the separatist group was to blame for the bombings, saying they were a "cost" of the government's military campaign against the rebels.
But PKK leader Zubeyir Aydar said his group was not linked to the attacks, suggesting they might have been carried out by "dark forces", in an apparent reference to ultra-nationalists.
Sunday's blasts occurred about 10 minutes apart on a busy pedestrian street in Gungoren. Five children were among the dead.
They were the worst such attacks in Turkey since 2003, when al Qaeda carried out a series of bombings in Istanbul.
Some 40,000 people have been killed since the PKK launched its campaign for self-rule in mainly Kurdish south-east Turkey in 1984.
Turkey's military has staged regular bombing raids into northern Iraq in recent weeks, bombing areas of the mountains where the PKK has bases.