Jerusalem ? In back-to-back attacks Sunday, a Palestinian suicide bomber blew himself up in front of a Jerusalem bus and a Palestinian gunman killed a teen-age girl in a shooting spree near Tel Aviv.

Visiting U.S. envoy Anthony Zinni condemned the violence but managed to arrange a meeting between security commanders Sunday as part of his attempts to mediate a cease-fire amid the worst spate of bloodshed in nearly 18 months of Mideast fighting.

Also, Israelis sent tanks to Bethlehem, moving within 200 yards of the Church of the Nativity, built on the spot where tradition holds that Jesus was born. One Palestinian militiaman was killed in an exchange of fire, and Israel later pulled back to its former positions near the edge of town.

Despite the confrontations, Israel Defense Minister Binyamin Ben-Eliezer said he was optimistic a cease-fire could be reached soon.

“The declaration of a cease-fire can be achieved within 48 hours,” Ben-Eliezer told Channel Two TV. “The problem is what will happen after a declaration of a cease-fire.”

No decisive steps taken

Zinni has sounded optimistic during his four days in the region but has yet to arrange face-to-face talks between the two sides. And while there have been hints of progress and pledges to work toward a cease-fire, neither side has taken the decisive steps the other is demanding.

Zinni held talks for a third straight day with Palestinian leader Yasser Arafat in his West Bank headquarters of Ramallah, and also conferred with Israeli President Moshe Katsav in nearby Jerusalem.

During the Katsav meeting, news broke of the shooting attack in Kfar Saba, just north of Tel Aviv, where a gunman opened fire with a pistol at a busy intersection just as schools nearby were about to let out. A 16-year-old girl was killed and six people were wounded before police shot and killed the attacker.

The shooting was carried out by Amar Shakhshear, 25, an activist in the Fatah movement headed by Arafat, Fatah sources said in Nablus in the West Bank. However, the sources said Shakhshear acted on his own and was not authorized to carry out the attack.

A short time later, a suicide bomber set off his explosives near a bus in a Jewish neighborhood in east Jerusalem, killing himself and covering the bus and the street with his flesh and blood. A few passengers on the bus were lightly injured, authorities said.

The militant group Islamic Jihad claimed responsibility for the bombing. A statement issued in Damascus, Syria, said the attack was in response to “crimes against our unarmed Palestinian people.”

‘Take responsibility’

Denouncing the bombing, Zinni said it was “critical that the Palestinian Authority take responsibility and act against terror.”

“Now is the time to get to a cease-fire,” Zinni said in a statement.

Before Sunday’s attacks, Israel said it was willing to meet a key Palestinian demand and withdraw its troops from areas under Palestinian control.

Israeli and Palestinian security commanders were meeting in the West Bank and the Gaza Strip late Sunday, senior Palestinian official Ahmed Qureia said. Qureia and Ben-Eliezer strongly suggested the meeting meant the sides have agreed to coordinate an Israeli pullout from the Palestinian areas in the near future.

A three-way security meeting headed by Zinni could take place as early as today if the Israeli troops withdraw first, Qureia said. Vice President Dick Cheney is slated to visit the region today with a meeting with Israeli Prime Minister Ariel Sharon.

Pulling back forces

In its largest military operation in a generation, Israel has entered more than a half-dozen Palestinian cities and refugee camps in the past two weeks in response to a wave of bombing and shooting attacks on Israeli targets.

Israel has since pulled out of all the areas except Bethlehem and Beit Jalla, neighboring West Bank towns just south of Jerusalem.

“Israel has offered a cease-fire, pulled back most of its forces in good faith, and this seems to be the answer Israel is receiving,” Dore Gold, a Sharon adviser, said in reference to the Palestinian attacks.

Before a Cabinet meeting, Sharon told reporters Israel will enter political negotiations with the Palestinians only after a cease-fire is in place. “My main aim is to achieve as soon as possible a cease-fire.”

The Palestinians have demanded that Israel withdraw from Palestinian areas before substantive negotiations on a cease-fire begin.

“Why should we give anything in return for an invasion?” said Palestinian Information Minister Yasser Abed Rabbo. “Israel should withdraw from the areas under Palestinian Authority control before starting any talks and negotiations.”

The U.S. truce plan was negotiated last May by CIA director George Tenet and endorsed by both sides, but has not been carried out.

It calls on the Palestinians to rein in militants and collect their weapons. Arafat has been reluctant to do that at a time when Israel has been carrying out attacks against Palestinian targets, including Arafat’s own offices.

The U.S. plan also says the Israelis must pull back their forces to where they were before the fighting began. That would involve the dismantling of many military checkpoints and roadblocks in Palestinian areas.

U.S. monitors?

Palestinian chief negotiator Saeb Erekat said Arafat was committed to working with Zinni on implementation of the Tenet plan. “And we need monitors to monitor the implementation by both sides,” he told CNN’s “Late Edition” on Sunday.

White House spokesman Sean McCormack said the Bush administration was open to considering U.S. monitors.

“If both parties thought monitors would be an action that would make a positive contribution, and both parties would have to agree, we would consider the request,” he said.

In other violence Sunday, an apparent Palestinian suicide bomber prematurely blew himself up in a West Bank valley outside Jerusalem, Israeli authorities said.

And in what appeared to be another instance of vigilante justice, Palestinian gunmen shot a Palestinian man in the West Bank town of Hares for reportedly selling land to Israeli settlers, Palestinian security officials said.

More than 190 Palestinians and more than 60 on the Israeli side have been killed since the beginning of March.