RAMALLAH, West Bank (AP) — Angry demonstrators clashed with Palestinian security forces for a third day Saturday during a protest in the West Bank over the death of an outspoken critic of the Palestinian Authority who died while in custody.

Hundreds gathered in the city of Ramallah — the headquarters of the PA — to chant slogans against President Mahmoud Abbas, two days after Abbas’ forces beat activist Nizar Banat shortly after his arrest.

The protesters held Palestinian flags and posters of Banat, and called on Abbas to quit. “The people want to overthrow the regime,” they chanted along with, “step down, Abbas!”

As the protesters began to march to Abbas’ office compound, a group of the president's supporters blocked the rally, prompting an exchange of stone-throwing between the two sides. Palestinian security forces in riot gear fired tear gas and stun grenades at the protesters, sending many running away for cover.

Later, Abbas’ supporters gathered in a counter rally, with many chanting: “People want Abbas as president.”

On Thursday, demonstrators had set fires, blocked the streets of the city center and clashed with riot police in Ramallah. Palestinians also chanted against the PA at Banat's funeral in Hebron and masked gunmen fired shots into the air. Hundreds also rallied against Abbas after Friday prayers at the Al-Aqsa mosque in Jerusalem.

The crackdown comes as the internationally-backed PA faces a growing backlash from Palestinians who view it as corrupt and increasingly autocratic, a manifestation of a three-decade peace process that is nowhere close to delivering Palestinian independence.

The PA controls parts of the Israeli-occupied West Bank, while its rival, the militant Hamas group, has controlled the Gaza Strip since 2007. Abbas, who was elected to a four-year term in 2005, has little to show after more than a decade of close security coordination with Israel.

The EU has provided hundreds of millions of dollars in aid to the Palestinian Authority over the years, and the U.S. and other nations have trained and equipped its security forces. The PA is seen internationally as a key partner in efforts to revive the Middle East peace process, which ground to a halt more than a decade ago.

In a series of posts and live videos on his Facebook, Banat had talked about the PA’s close security coordination with Israel, seen by many Palestinians as betrayal, and its corruption. He severely slammed Abbas in April for calling off what would have been the first Palestinian elections in 15 years. Banat was a candidate on a slate formed of academics and PA opponents.

The PA said it formed a high-level committee to investigate Banat’s death. His family said he was beaten in custody. An initial forensic examination concluded the cause of the death was “unnatural.”

Associated Press writer Fares Akram in Cairo contributed to this report.