A powerful explosion ripped through the mall pizzeria of a Jewish settlement in the West Bank Saturday, killing three people and wounding 27.

West Bank police Chief Shahar Ayalon said the explosion was set off by a suicide bomber. Those killed were the assailant, an Israeli woman and a boy.

A radical PLO faction, the Popular Front for the Liberation of Palestine, claimed responsibility some hours later in a phone call to satellite TV station Al Jazeera.

The blast went off shortly before 8 p.m. in the Karnei Shomron settlement, about 25 miles northeast of Tel Aviv.

It marked the first time in 16 months of fighting that a settlement was targeted in a bombing.

The Saturday evening blast capped a violent day in which four Palestinians were killed. One of the Palestinians, a senior member of the Islamic militant group Hamas, was killed in an explosion blamed on Israel, and the group threatened retaliation.

"The pizza place is totally burned, totally destroyed," a paramedic, identified only by his first name, Shia, told Israel TV's Channel 1.

The TV report said the explosion was set off in the midst of diners at the pizza restaurant. The mall was poorly guarded, despite warnings about plans by Palestinian militants to carry out bomb attacks, according to the report.

The Associated Press contributed to this report.