A fire swept through a mosque in this Palestinian village early Tuesday, angering Palestinians who said they were certain that extremist Israeli settlers were to blame, although investigators have found no proof. The Palestinian president, Mahmoud Abbas, echoed those sentiments and warned that the blaze “represented a threat to the efforts to revive the peace process.”

Although the Israeli authorities were still investigating the cause of the fire late Tuesday and had not yet established that it was arson, the Palestinians’ conviction that it was the work of Israeli settlers was a reflection of the charged atmosphere in the Israeli-occupied West Bank ahead of a long-awaited resumption of peace talks.

The Obama administration’s envoy, George J. Mitchell, is scheduled to shuttle between the Israeli and Palestinian leaders this week, marking the beginning of the so-called proximity talks — the first peace negotiations in more than a year.

But in this village south of Nablus, emotions were running high.

“There is no doubt that those who committed this act are settlers,” said Majed Ismail Daraghmeh, leader of a committee responsible for recent renovations at the mosque.

As evidence, Mr. Daraghmeh pointed to a collection of Korans that had been neatly arranged in a semicircle and two piles before being burned in the fire and chronicled other incidents in recent years, like the burning of an olive press and of cars in the area, for which he also blamed settlers.

A string of Palestinian politicians and religious leaders toured the charred interior of the mosque on Tuesday, including the prime minister of the Palestinian Authority, Salam Fayyad, and the Palestinian grand mufti of Jerusalem, Muhammad Hussein. Groups of local schoolchildren also filed through.

A legislator from the Islamic militant group Hamas, Hamed Bitawi, said the fire showed that “the Jews are killers, terrorists and criminals.” He added, “Our people should reconsider their strategy with them.”

Among other things, Israeli investigators, who examined the scene together with Palestinian security officials, were checking whether the fire could have started from an electrical fault. Islamic holy books were piled up on the floor in other parts of the mosque that were not damaged by the fire, having been removed from their shelves because of the renovations.

No Hebrew graffiti was found in or around the mosque, nor was there any obvious sign of a break-in.

But tensions have been running high between the Palestinians and extremist settlers in the area. In December, a mosque in the village of Yasuf, also south of Nablus, was attacked by arsonists who left a message in Hebrew. Several settlers were questioned by the Israeli police in connection with the fire, but none were charged. Last month, a mosque in the nearby village of Hawara was vandalized; a Star of David and Hebrew letters spelling the name Muhammad were spray-painted on an outside wall.

Also Tuesday, an olive orchard on the outskirts of Hawara was scorched. Local residents accused settlers of intentionally setting it on fire.

Some on the radical fringe of the settler movement have adopted a provocative policy known as “price tag,” which calls for an aggressive reaction to any attempt by the Israeli military or police to remove or destroy unauthorized property in official settlements or illegal outposts.

On Monday, the Israeli authorities destroyed several structures in the settlement of Shavei Shomron that were being built in violation of Israel’s partial settlement freeze.