US peace envoy George Mitchell met Palestinian President Mahmoud Abbas on Friday to try to break a diplomatic impasse that some say could give rise to a new Palestinian uprising, or intifada.

After a nearly year-long vacuum in negotiations, Palestinian and Israeli peace activists say that Israel has escalated arrests of protesters to prevent wide-scale demonstrations.

"Since June we feel arrests have increased," said Mohammed Khatib, an activist from the village of Bilin, where weekly protests against Israel’s separation fence have been held for years. "The struggle is becoming more effective in and outside of Palestine. Israeli authorities want to stop it before it will become a third intifada.’ "

In the past six months, the army has detained some three dozen activists in the village, roughly comparable to the number of arrests going back several years, he said.

In East Jerusalem last week, police arrested the director of the Association for Civil Rights in Israel, Hagai El Ad, at a protest against the displacement of a Palestinian family from property owned by Jews. Elsewhere, Israel’s Interior Ministry sent officers with a military escort into Ramallah to arrest a Czech activist with the International Solidarity Movement whose visa had expired.

"The Israelis are afraid of the popular protest model spreading," said Jonathan Pollak, an Israeli peace activist who said the army has carried out 15 round-ups of antibarrier protesters in the village of Niilin in a month. "They are terrified of this model gaining momentum, and are setting out to quash it."

A spokesman for Israeli Prime Minister Benjamin Netanyahu said the protests in the West Bank are "illegal'' because they involve throwing rocks and homemade petrol bombs at soldiers.

"If you’re behind violence, you are behind illegal activities. These are not peaceful protests, far from it," said spokesman Mark Regev. "The current policy of the Palestinians not to negotiate is harmful to all those who seek peace, and is harmful to themselves because it ultimately plays into the hands of extremists like Hamas."

Mr. Netanyahu and President Abbas have accused each other of taking steps that are not far-reaching enough to renew political talks. The daily newspaper Haaretz reported Thursday that Israeli President Shimon Peres said he warned Abbas that a new intifada is liable to break out if the renewal of peace talks continues to be delayed.

Experts, however caution that those predictions should not be overstated. Though there’s talk of organizing civil unrest against Israel, the movement is currently in its infancy, said Gershon Baskin, the copresident of the Israel Palestine Center for Research and Information.

"Israel is taking very seriously these weekly demonstrations. I’m sure the Shin Bet [security service] is aware of what is going on," he said. Though it’s not yet a mass movement, "if settlement building continues … anything could spark it."