Terror attacks against Israeli targets in the West Bank and Jerusalem increased sharply in September 2012, as compared to August, the Shin Bet security agency reported on Wednesday.

According to the report, there were 91 attacks registered in September, compared to 51 in August. The majority of the incidents were Molotov cocktail attacks.

In addition, during September, terrorists in the Gaza Strip fired 17 rockets and eight mortar shells at Israel in 25 separate incidents, compared to 21 rockets and three mortar shells in 16 incidents in August.

Earlier in September, an elite Israeli undercover unit was reported to be carrying out frequent nightly missions into Palestinian territory and training for the possible outbreak of a third intifada, fearful that the current fragile calm in the West Bank could give way to a surge in Palestinian violence.

“We need to be alert and stay one step ahead,” the commander of the IDF’s Duvdevan unit told Israel’s Channel 10 news. “The potential for another uprising exists and we have to prepare ourselves for such an eventuality,” said the officer, a lieutenant-colonel who was identified only as S.

Israel battled a mass uprising in the territories between 1987 and 1993 — the first intifada — and an onslaught of suicide bombings and other terrorist attacks from late 2000 — the second intifada. That terrorism declined after Israel built a security barrier, physically cutting off access from the West Bank into Israel.

Ron Friedman contributed to this report.