The four new patients are migrant workers; three of them had recently returned to the district from Mumbai and one from Ahmedabad, said Muzaffarnagar DM Selva Kumari J.
She said the workers were staying at a quarantine centre in Baghra.
The authorities had sent 136 samples for COVID-19 testing and four of them, belonging to the migrant workers, came back positive, the district magistrate said.
The remaining 132 came back negative for the novel coronavirus, she added.
Meanwhile, Ladhawala in the district has been sealed after an ambulance driver from the locality was found COVID-19 positive on Thursday, officials said. CORR AD