Eritrea was ranked last by the media watchdog, taking over from last year's lowest-ranked country, North Korea.
Among the most significant declines were Afghanistan, (which fell 26 places to 178th), Togo (down 43 to 113th) and Ecuador (down 30 to 110th).
The bottom 10 included China, Iran, North Korea, Syria and Eritrea.
But Reporters Without Borders, known by its French acronym RSF, warned that politicians across a wide range of countries were targeting the media.
"Some political groups fuel hatred and distrust of journalists by insulting them, discrediting them, and threatening them," RSF said, adding "others are orchestrating a takeover of the media ecosystem."
The media watchdog singled out Argentina under newly elected President Javier Milei, down 26 places to 66th, saying his decision to shutter the public press agency Telam was a "worrisome symbolic act."
RSF also highlighted Italy under Prime Minister Giorgia Meloni, where a member of her coalition is trying to acquire news agency AGI.
Respondents in three-quarters of countries (138) reported to RSF that political actors were often involved in disinformation and propaganda, and that this was systematic in 31 countries.
RSF said there was "spectacular mimicry of Russian repressive methods" across Eastern Europe and Central Asia, stretching as far as Serbia, "where pro-government media carry Russian propaganda and the authorities threaten exiled Russian journalists."
The most challenging region remained the Middle East and North Africa, where the situation was "very serious" in nearly half the countries, with Qatar now the only country where the situation was not classified either as "difficult" or "very serious."
Europe was the only region to include any countries classed as "good."
Greece was ranked worst in Europe (88th overall), coming below Hungary and Poland.
Despite improvements in its score, Greece was criticized over its continued failure to deal with a scandal around wiretapping journalists by the intelligence service and the murder of veteran crime reporter Giorgos Karaivaz in 2021.
Now in its 22nd year, the RSF report is based on data collected by the group about abuses against journalists, and questionnaires sent to professionals, researchers and rights defenders.
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