Northern Ireland's senior judge ordered the immediate release of six suspected republican dissidents being interrogated over recent killings of soldiers and police, ruling that their 11-day detention was illegal.

Detectives released the suspects but rearrested the most prominent figure in the group, former Irish Republican Army man Colin Duffy, without explanation.

The other five covered their faces as supporters drove them away from a police interrogation centre at high speed.

Lord Chief Justice Brian Kerr said a lower-ranking judge who extended their detention last weekend to 14 days had mishandled the case.

A 17-year-old boy and former Sinn Fein politician Brendan McConville were arrested on March 10 and charged this week with killing a policeman and possessing an assault rifle and ammunition.