Schools in Swansea continue to be a safe place during the coronavirus pandemic, a cabinet member has said, with only 1.1% of pupils testing positive since the start of term in September.
Cllr Jennifer Raynor thanked parents for their support, but said there had been some mixing outside of school.
She said: "Please, no more parties, no more sleep-overs, and very careful sending round to grandparents for childcare."
Addressing a meeting of full council, Cllr Raynor said 365 out of 31,500 pupils, from reception to year 11, had been positive cases as of December 2.
This compared to 215 out of 3,570 school staff testing positive during that time - a 6% rate.
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Cllr Raynor said 19,417 pupils and 871 school staff had been asked to isolate, in addition to the positive cases, as per the guidelines.
She added that schools had been commended by visiting Health and Safety Executive officers, and had followed Welsh Government advice to keep classes and year groups together.
"We really need to congratulate our schools, especially the teachers and heads, who have organised this absolutely brilliantly," she said.
Cllr Raynor, who holds the education brief, said Public Health Wales had confirmed that most positive cases were in the community, as opposed to spreading within schools.
She thanked parents in Swansea for their support when their children were isolating, which she said was "no mean feat".
Cllr Raynor said: "There are, however, cases where pupils have not been isolating, and families have not been quite as supportive.
"And there has been meeting up with other pupils from different classes, different year groups, different schools and there has been movement around families.
"So we request that the families limit the contact of their children within our communities."
