Government spokesman Ghassan Khatib acknowledged occasional lapses, but said that in the past two years, there's been great progress and success in reducing abuses.

Such promises mean little to atheist blogger Walid Husayin, who has lived in fear of the security forces since being released from a nine-month prison stint last summer.

I'm sick and tired. My life has come to a halt, the 28-year-old Husayin said in a phone interview from his home in the northern West Bank town of Qalqiliya.

Since his release on bail, he has been picked up several times by security agents and held for days at a time. In one of those detentions, he was beaten with cables and forced to stand in a painful position on empty cans, said Husayin, the son of a Muslim preacher. Interrogators smashed his two computers and demanded that he stop expressing his views, he said.

Activists from three rights organizations said they witnessed an increase in arbitrary detentions in recent months, including calling in troublemakers for repeated interrogation, but said they hadn't yet collated 2011 figures.

Those targeted include loyalists of the Islamic militant Hamas, Abbas' political rival, and supporters of Hezb al-Tahrir, or the Liberation Party, a puritan Islamic movement considered apolitical.

The increased pressure on dissent coincides with pro-democracy uprisings of the Mideast Arab Spring, but it's not clear if there is a direct link. Anti-government demonstrations in the West Bank usually draw just a few dozen or few hundred people, tiny compared to protests that toppled rulers in Egypt, Libya and Tunisia over the past year.

There appears to be little popular sympathy for those targeted in the crackdown, said Jamil Rabah, an independent Palestinian pollster.