A fifth man has been arrested by detectives investigating a car bomb blast outside a court in Londonderry.

The man, 50, was detained under the Terrorism Act. Four men arrested on Sunday remained in police custody on Monday afternoon.

Officers probing the dissident republican bombing on Saturday night arrested the latest suspect for questioning about an armed robbery in the city last Tuesday.

The arrest came as police investigated two vehicle hijackings in the Creggan area of Derry on Monday.

In the first incident, three masked men reportedly hijacked a white Transit van in the Circular Road area at around 11.30am before throwing an object in the back and abandoning the vehicle.

Just over two hours later, at 1.45pm, police received a report that four masked men – one allegedly armed with a gun – hijacked a delivery driver’s vehicle on Southway.

Police said the two occupants of the van were ordered to drive the vehicle to the Lonemoor Road and leave it there.

Both incidents have prompted significant security alerts, with nearby residents evacuated and Army bomb disposal experts deployed.

Police Service of Northern Ireland (PSNI) Superintendent Gordon McCalmont warned of widespread disruption.

“We understand the effect this will have on the local community, but we will not take any chances when it comes to keeping people safe,” he said.

A dissident republican grouping that styles itself as the New IRA has been blamed for the bombing on Bishop Street.

Dramatic CCTV footage of the incident released by police showed a group of people walking past the car containing the bomb just minutes before the explosion.