Most of the 27 COVID-19 patients in Daman are factory workers who cross the border to work in industrial units at Vapi in neighbouring Gujarat and vice versa, the officials said.
The eight fresh cases were reported on Friday.
"The district administration has closed all border check-posts with Gujarat for a few days due to clustering of cases near the border areas, and has declared several parts of Dabhel village, an industrial hub, as containment zones in an effort to control the spread of coronavirus," an official said.
Vehicles holding valid e-passes are also not being allowed to enter Daman, he said.
Daman had reported its first two COVID-19 cases on June 9, a few days after the Union Territory said the district was coronavirus-free due to the strict implementation of lockdown measures.
"Out of the 27 cases in Daman, around 20 patients are factory workers who travel frequently through border check- posts. Due to the clustering of cases near the areas bordering Gujarat, the district administration has temporarily closed the border for a few days," programme officer for communicable diseases, Meghal Shah said.
Several workers travel to neighbouring Vapi in south Gujarat to work in factories there, while a number of them s travel from Vapi to Daman for work in industrial units.
Diu district of the UT had also reported its first two cases on June 12.
The number of cases here has now risen to 10, with five new cases reported on Saturday alone, collector Saloni Rai said.
In a tweet, Rai said, "Five more cases tested positive today. All of them had travelled via flight to Diu and were under facility quarantine. Total active cases in Diu district: ten."
The number of cases in Dadra and Nagar Haveli also grew to 49.
With this, the UT of DNH, Daman and Diu has so far reported 85 cases, out of which 70 cases are active.
According to the health department of the UT administration, a total 27,239 samples have been collected for COVID-19 tests.
Results of 701 are awaited, it said.
As many as 16,986 samples have been collected in DNH, 8,430 in Daman and 1,843 in Diu.
A total 2,696 persons are under surveillance, including 1,597 in DNH, 615 in Daman and 484 in Diu. COR KA PD NP NP