Delhi Deputy Chief Minister Manish Sisodia, who was admitted to hospital a day ago after earlier having tested positive for the coronavirus, also has dengue, officials said on Thursday.
Mr Sisodia, who was admitted to the city's Lok Nayak Jayaprakash Hospital with fever and complaints of breathing difficulties, has falling levels of blood platelets, doctors said. Later in the evening, he was shifted to a private hospital in Saket.
He had been under self-isolation at his official residence since testing positive for the highly contagious disease on September 14.
Patients who do not have co-morbidities or complications and do not belong to the vulnerable age group are advised home quarantine.
On September 14, Mr Sisodia had tweeted to announce his positive status and warn those who came in contact with him.
"After suffering from mild fever, I took a coronavirus test and turned out to be positive. I have isolated myself. I don't have a fever or any other problem as of now, I am absolutely fine. With your prayers, I am sure I will return to work after regaining my health," he tweeted in Hindi.
The 48-year-old, along with other ministers, had been actively involved in Delhi's fight against the pandemic, addressing virtual press briefings, inspecting Covid facilities and overseeing the management of the disease.
With 3,834 new coronavirus cases, Delhi's infection tally crossed 2.6 lakh on Thursday, while the number of deaths climbed to 5,123, authorities said. Thirty-six deaths due to COVID-19 were recorded in the last 24 hours.
Delhi Chief Minister Arvind Kejriwal, meanwhile, said the second wave of the coronavirus pandemic has hit its peak in the national capital with experts hinting that the cases of infection will decline in the coming days.
He said the government was "keeping its fingers crossed" and hoped that COVID-19 cases will "gradually" come down due to the steps taken by the Aam Aadmi Party administration as he tried to allay fears over the surge in the number of coronavirus cases in the last few days.