The coronavirus pandemic may threaten press freedom and worsen the crises that reporters around the world are facing, according to this year’s World Press Freedom Index, which evaluates the landscape for journalists in 180 countries and territories.

The report, published on Tuesday by the media watchdog group Reporters Without Borders, said the United States and Brazil were becoming models of hostility toward the news media. It also singled out China, Iran and Iraq for censoring coverage of the coronavirus outbreak.

The pandemic has already redefined norms. New laws that some governments have passed with the ostensible goal of slowing the spread of the virus — ones that broaden state surveillance, for instance — have raised concerns about long-term negative effects on the news media and freedom of expression.

The pandemic has allowed governments to “take advantage of the fact that politics are on hold, the public is stunned and protests are out of the question, in order to impose measures that would be impossible in normal times,” Christophe Deloire, the secretary general of Reporters Without Borders, said in a statement.