The International Press Institute (IPI) has registered its concern over the treatment of Palestinian journalists by both Israeli forces and Palestinian security services.

The press freedom watchdog says that since the beginning of 2012, at least five journalists working in the Palestinian territories have been subjected to arbitrary arrest. Two more have had their detention periods extended.

Three of those who were arrested recently were allegedly interrogated for several hours about their writing before being released. The other two remain in custody.

IPI's executive director Alison Bethel McKenzie said the detentions appear to reflect a desire to control information and silence criticism "neither of which is acceptable in a democratic society."

She said: "The pattern of interrogating journalists for what they write and then later releasing them appears to be a method of encouraging self-censorship, something that is ultimately most harmful to the people of Palestine."

The two journalists still in detention following their arrests by Israeli forces on 5 February were named as Suhaib Al-Asa, a reporter with Radio Bethelem 2000, and Oman Halaiqaa, a photojournalist based in al-Khalil province.

On 3 February, Palestinian security forces arrested Rami Samara, an editor at the official Palestinian news agency Wafa, and questioned him for three hours about criticisms of the PLO leadership posted on his Facebook page.

And Yousef Shayeb, a correspondent for the Jordan-based al-Ghad newspaper, said he was held for eight hours on 31 January and questioned about his stories alleging corruption at a Palestinian diplomatic mission abroad.

The Israeli military has denied claims that it directly targets journalists. "There is no such policy and I would even say it's ridiculous to make such a claim," said a spokesman.