Hamas's leader in Gaza, Yehya Al Sinwar, tested positive for Covid-19, a spokesman for the militant group that runs the Palestinian territory said on Tuesday.
Mr Al Sinwar, 58, is "following the advice of health authorities and taking precautionary measures", spokesman Hazem Qassem said. He did not say if the Hamas chief was in quarantine.
"He is in good health and he is pursuing his duties as usual," Mr Qassem said.
Mr Al Sinwar, a former head of Hamas's security apparatus, became the movement's Gaza leader in 2017, six years after he was freed in a prisoner swap with Israel after more than 20 years in jail.
Gaza has logged nearly 21,000 coronavirus cases and 111 deaths, mostly since August, amid concern of a wider outbreak in the densely populated enclave of two million people.
Coronavirus around the Middle East today - in pictures
The World Health Organisation this week delivered 15 ventilators to Gaza hospitals to help treat the most sick patients with Covid-19 as a surge in infections tests the Palestinian territory's underdeveloped health system.
The donation of the intensive care devices, funded by Kuwait, came a week after local and international public health advisers said hospitals in the enclave could soon be overwhelmed.
"These devices will help medical teams provide better service to patients, but it is not enough," said Abdullatif Alhaj, of Gaza's health ministry.
Mr Alhaj said hospitals had suffered acute shortages of oxygen, which is essential in the treatment of Covid-19 patients.
The Gazan Health Ministry said more than half of the territory's 150 ventilators are in use.
"The health system right now can hold on for a few weeks after the expansion of beds," said Abdelnaser Soboh, emergency health lead in the WHO's Gaza sub-office.
Mr Soboh said Gaza is also experiencing severe shortages of medications and disposable equipment needed to treat Covid-19 patients.
Palestinians in Hamas-run Gaza say 13 years of economic sanctions by Israel and its border blockade have crippled their economy and undermined the development of medical facilities, weakening their ability to tackle the pandemic.
Israel, which cites security concerns for the border restrictions it imposes, along with neighbouring Egypt, says it has not limited the transfer of medical supplies to Gaza to fight the pandemic.
