Jerusalem ? A Palestinian woman set off explosives at an Israeli roadblock Wednesday in the West Bank, killing herself and wounding two companions and two Israeli police officers, police said.

“The woman suicide bomber got out of the car and blew herself up,” said Shachar Ayalon, the Israeli police commander in the West Bank. He said two other Palestinians who were in the car had severe injuries. “They are on the ground and are in serious condition,” he told Israel radio.

The bombing came after Israeli troops killed four armed Arabs in gun battles, and a Palestinian employee shot dead an Israeli factory manager in an attack that was apparently politically motivated.

A woman suicide bomber is a rarity, though more than 30 Palestinian men have carried out such attacks. On Jan. 27, Wafa Idris, a 27-year-old Palestinian paramedic, blew herself up in downtown Jerusalem, but it was unclear whether she planned to commit suicide. An 81-year-old Israeli man also died in that attack.

Early today, Israeli tanks around the Balata refugee camp next to Nablus moved closer to the camp and fired two missiles, Palestinians said. One missile knocked out electricity in the camp, a stronghold of armed militias linked to Palestinian leader Yasser Arafat’s Fatah movement.

Israeli tanks have held positions for several days on the Nablus street across from the camp, a known center for armed militias affiliated with Fatah. The militias have claimed responsibility for many recent attacks against Israelis. A Palestinian was killed in a clash there early Wednesday.