Israel has joined a notorious band of authoritarian states with a history of imprisoning journalists by detaining Palestinian reporters without trial since the beginning of the latest war in Gaza.

Related: Israeli military accused of targeting journalists and their families in Gaza

A report by the Committee to Protect Journalists (CPJ) released on Thursday said that for the first time Israel figures in its list of “worst jailers of journalists”, putting it on a par with Iran.

The worst offenders were China and Myanmar, two countries with a long history of suppressing free speech where each imprisoned more than 40 journalists in 2023. They were followed by Belarus, Russia and Vietnam.

Israel is in sixth place after the CPJ recorded 18 Palestinian journalists in its jails, the first time the country has been featured among the worst offenders. Others were detained and released. Iran was immediately behind Israel.

Jodie Ginsberg, CPJ’s chief executive, said Israel’s inclusion on the list of detained journalists reflects a broader crackdown on free speech and criticism of the war in Gaza.

“Israel’s standing in CPJ’s 2023 prison census is evidence that a fundamental democratic norm – press freedom – is fraying as Israel exploits draconian methods to silence Palestinian journalists. This practice must stop,” she said.

The CPJ said Palestinian journalists are mostly held under the Israeli military’s powers to detain people in the occupied territories without trial or time limit. The practice, known as administrative detention, permits the army to arrest a person on suspicion alone. Some Palestinians have been held for years without charge.

The Israeli human rights group B’Tselem said it is almost impossible to mount a defence against the detention.

“The person is detained without legal proceedings, by order of the regional military commander, based on classified evidence that is not revealed to them. This leaves the detainees helpless – facing unknown allegations with no way to disprove them, not knowing when they will be released, and without being charged, tried or convicted,” it said.

The CPJ said the Palestinian journalists were among 320 reporters and other media workers imprisoned around the world. One in five were held without charge.

“Prolonged pretrial detentions and cruel treatment are common, while some governments, such as Russia and Ethiopia, have even persecuted journalists across borders. In Vietnam, Egypt, and other countries, even after their release, journalists continue to face travel bans, other movement restrictions, and measures that effectively curtail their freedom,” the report said.

The detained Palestinian journalists include Alaa al-Rimawi, the director of a West Bank news agency, J-Media, which was banned by Israel on security grounds. The presenter of a popular radio phone-in show, Tarek el-Sharif, who the CPJ said “provided daily updates for his listeners on Israel’s military response, discussing airstrikes in Gaza and the Palestinian death toll with local callers”, was arrested in November and charged with incitement.

Others detained include journalists with a Ramallah-based television station, a freelance cameraman for Al Jazeera and Jordanian television, and a correspondent for a London-based press agency.

The arrests are part of a broader pattern of risks for journalists reporting the Israel-Gaza war. The CPJ says at least 83 media workers have been killed in Gaza, most of them Palestinian.

The CPJ said it has also documented multiple kinds of incidents of journalists targeted in Israel and Palestine, including “numerous assaults, threats, cyberattacks, and censorship”.