Kurdish guerrillas were behind a double bombing in Istanbul last week that killed 17 people, Turkey's interior minister said on Saturday, adding that all those involved in the attack had been caught.

The blasts, 50 metres (160 ft) and 10 minutes apart, were the worst such attacks in Turkey since 2003 when al Qaeda carried out a series of bombings in Istanbul. Some 150 people were injured in last Sunday's explosions.

"Our judgement is that this merciless attack was the work of the bloody separatist terror group," Interior Minister Besir Atalay told a televised news conference.

"Those who helped, those who gave shelter and those who took part in the attack have been caught."

Government officials had already indicated they suspected the Kurdistan Workers Party (PKK) guerrilla group was responsible for the attack. The PKK has denied involvement and there have been no claims of responsibility.

An Istanbul court on Saturday evening remanded in custody eight detainees in connection with the attack after a prosecutor accused them of PKK membership, state-run Anatolian news agency reported. The prosecutor will now prepare an indictment formally charging them.

The rebel group took up arms against the Turkish state in 1984 with the aim of establishing an ethnic homeland in the southeast of the country.

Some 40,000 people have been killed in the conflict with the PKK, which Turkey, the United States and European Union consider to be a terrorist organisation.