Resurgent virus cases have forced a new closure of major museums and the zoo in Washington, officials said Thursday, hitting the brakes on the U.S. capital's cautious and limited resumption of activity.

The National Zoo and SOME museums had reopened from late July, after the pandemic forced shutdowns, with crowd-size limits and social distancing requirements.

"Due to rising regional and national cases related to the COVID-19 pandemic, all Smithsonian museums, including the National Zoo, will temporarily close to the public starting Monday," the renowned Smithsonian Institute said in a statement.

Officials did not offer a possible reopening date.

The capital city, where 667 deaths have been reported of COVID-19 since the start of the pandemic, has been largely at a standstill. Movie theaters remain closed, and restaurants can only operate at half capacity.

The United States has seen a surge in infections and deaths in recent weeks, with reported cases at over 11.6 million and more than 251,000 fatalities, according to the Johns Hopkins University tally. 

Cities around the nation were stepping up restrictions and face mask requirements in a bid to curb the spread as the winter cold and flu season loomed.