UPDATE 1-Van reportedly seized and abandoned in N.Ireland, days after car bomb

Northern Ireland police cordoned off a residential street in Londonderry on Monday to examine a van for potential security threats. "A white Transit van was reportedly hijacked by three masked men who threw an object in the back of it before abandoning it,"a spokesman said.

On Saturday, a car bomb exploded outside the city's courthouse in a vehicle that had also been hijacked by masked men. No one was injured. "We anticipate significant disruption to the local community while we work to the make the scene safe," the spokesman said.

Police also arrested a fifth man on Monday in relation to Saturday's attack. The 50-year-old was detained under the Terrorism Act while four other men remained in custody, police said. The main focus of the car bomb investigation is the New IRA - one of a small number of groups opposed to a 1998 peace deal that largely ended three decades of violence in the British-run province.

(Reporting by Padraic Halpin in Dublin and Amanda Ferguson in Belfast; Editing by Kevin Liffey)