Britain's Secretary of State for Northern Ireland Karen Bradley arrives in Downing Street, London, Britain October 16, 2018. REUTERS/Hannah McKay

LONDON (Reuters) - Britain’s Northern Ireland minister Karen Bradley said it was essential to keep up vigilance in Northern Ireland after a car bomb exploded in Londonderry, but she added that the overall threat level in the province had not changed.

“Although there has been a reduction in the overall number of national security attacks in recent years, vigilance in the face of this continuing threat remains essential,” Bradley told parliament on Monday. [nL8N1ZL31X]

She said the threat level in Northern Ireland would remain at ‘severe’: “This attack does not change this threat level.”