LONDON: The government announced nine new swine flu cases Monday, including seven people who had not travelled to Mexico, health officials said, taking the total number of infections in Britain to 27.

"Seven of the nine cases appear to have been acquired through person-to-person spread. Two cases are in people who have recently returned from Mexico," a Department of Health statement said.

Seven of those diagnosed were children, officials said.

The school which five of the children attended in Dulwich, south London, became the fourth in Britain to be closed to prevent more infections.

The statement said that eight of the new cases were in London and one was in the West Midlands.

Earlier a 14-year-old girl from South Hampstead High School in north London was diagnosed with the virus.

Classrooms at the school, attended by the child from Barnet who is in year nine, have been closed until at least Thursday.

Authorities expressed confidence that the country's health services were well-equipped to contain the outbreak.

"The arrangements in place across the UK are continuing to ensure that we are well-placed to deal with this new infection," the statement said.

There are now 23 cases in England and four in Scotland. Ireland confirmed its first case on Saturday.

Most infected Britons have been treated with drugs in their homes.