Northern Ireland's Public Health Agency (PHA) has said there were 612 confirmed or probable cases of the Delta variant of Covid-19 detected throughout all 11 local council areas by yesterday.
The PHA said that around half of Covid-19 positive cases sampled in Northern Ireland are now indicative of the Delta variant.
The variant was first identified in India, and is now dominant in the UK. Up to Monday, a total of 449 people in Omagh and 689 in Ballymoney were tested after a number of probable cases were identified in the two towns.
Early analysis of results shows a total of 31 positive cases of Covid-19 were detected, the PHA said. All have been contacted and advised to self-isolate in line with public health guidance.