At least 21 journalists have been victims of reprisal killings so far this year, more than double the number from last year, the Committee to Protect Journalists said in a report Tuesday.
A total of 30 journalists were killed in the line of duty in 2020, according to a tally by the watchdog group.
The CPJ is still investigating the deaths of at least 15 other journalists this year to determine whether journalism was the motive.
Mexico was the most dangerous country for newsgathering with at least five journalists singled out for reprisal killings, the group said in its report.
"The fact that murder is on the rise and the number of journalists imprisoned around the world hit a record is a clear demonstration that press freedom is under unprecedented assault in the midst of a global pandemic, in which information is essential," CPJ executive director Joel Simon said.
"It's appalling that the murders of journalists have more than doubled in the last year, and this escalation represents a failure of the international community to confront the scourge of impunity."
The group expressed shock at the execution in Iran of journalist Ruhollah Zam on December 12 for his reporting on 2017 anti-government protests, calling the action "state-sponsored murder."
The number of combat-related deaths for reporters declined meanwhile to the lowest level since 2000, in view of pandemic-related travel restrictions. CPJ counted three such deaths, all in Syria.
Earlier this month, the organization reported a record number of journalists imprisoned in 2020, in line with a similar tally from France-based Reporters Without Borders.