A 35-year-old woman has been arrested by police investigating a dissident republican bomb attack on a prison officer in Belfast.
The suspect was detained in the city earlier and is being held at Musgrave serious crime suite, according to a PSNI spokesman.
Officers have also been granted an extra 24 hours to continue to question three men aged 34, 39 and 45 who were arrested on Sunday evening.
The prison officer, a 52-year-old married father-of-three, required surgery after an explosive device detonated under the van he was driving on Friday March 4.
It is understood he is now out of hospital.
A group calling itself the New IRA claimed to have carried out the attack.
In a statement to the BBC they said the officer was targeted because he was involved in training other guards at Maghaberry high security jail, near Lisburn in Co Antrim.
The terror group said he was one of a number on a list of potential targets and the attack arose from a dispute over the treatment of dissident Republican inmates.
They also claimed to have used the plastic explosive Semtex and a commercial detonator.
Following the blast, police commanders expressed fears that dissidents planned to step up the number of attacks to mark the centenary of the Easter Rising.