The shooting attack in the Hebron Hills on Tuesday could not have been a surprise. Palestinian opposition groups, especially Hamas, were highly motivated to embarrass the Palestinian Authority on the eve of the start of direct talks in Washington. A short conversation with the members of the Palestinian delegation to Washington Tuesday night shows that the mission was indeed accomplished.

They sounded stressed, angry and aware of the serious implications that this incident could have on the peace talks and their ability to maneuver vis-a-vis Israel. Moreover, the group sought to undermine the American summit and to send a painful reminder to the U.S. administration and the Israeli government that in order to resolve the Israeli-Palestinian conflict, they must also be made party to any deal.

Spokesmen for Hamas and Islamic Jihad did not hesitate last night to praise the terrorists, and especially the results of the attack. These groups have a long tradition of shooting attacks on cars on the eve of important peace summits. This is what happened before the Madrid Conference, during the Oslo Accords and even prior to the Annapolis conference in 2007. Earlier this week, Chief of Staff Gabi Ashkenazi toured Central Command and told the brigade commanders to step up readiness, out of concern that there will be those who may try to undermine the start of the peace talks.

Even though no official claim of responsibility was made, the investigation by the security services of Israel and the Palestinian Authority suggest that the culprits were a cell which identifies itself, more or less, with Hamas. Fauzi Barhum, one of the spokesmen for the group in the Gaza Strip, did not openly claim responsibility for the attack, but hinted that his group was behind the shooting.

"The resistance continues everywhere," he said.

In recent months the Hamas leadership in the Gaza Strip and Damascus has pressed West Bank-based teams of gunmen to resume the attacks in an effort to make it more difficult on the Palestinian Authority and stir up tension with Israel.

Two months ago a large Hamas network was uncovered in the southern Hebron Hills, a "sleeper cell" that was revived, whose members are suspected of murdering an Israeli policeman in a similar shooting incident, along the same route, several kilometers from the spot of last night's terror attack.

Tuesday night's attack suggests Hamas apparently still has the capability of relatively complex operations, with a high level of performance, despite the brutal repression of the Palestinian Authority security forces.

The fact that the murderers killed all the passengers in the car, apparently by "confirming" the kill at point-blank range, hints at cool headedness and expertise.

The security services in Israel and the PA are now in a race against the clock in order to track the killers down before the summit begins in Washington this evening. It is likely that the high degree of intelligence cooperation on display recently was partly shelved last night in favor of a race to get to the suspects first.

The attack does not suggest this is the dawn of a new murderous era in the West Bank, even though it is a particularly difficult incident - the worst in terms of casualties in recent years. The PA will also try to calm the situation and prevent more incidents, which may embarrass it vis-a-vis Israel.

The main risk in the coming days will stem from the tension between the Jewish and Arab populations in Hebron, where the atmosphere is tense because of the resumption of direct talks.

We can expect an attempt by the settlers to leverage an "appropriate Zionist response" in the form of an outpost in the area of the attack, ahead of the summit and the pending end of the settlement moratorium. In a more grave scenario, there could be revenge attacks on the Palestinians, or "price tag" retributions.

The settler leadership was quick last night to link the murder of the four residents of Beit Hagai to the broader political-security reality. In addition to the demand that the Prime Minister cancel his participation in the summit, they also demanded the resumption of construction in the West Bank and the re-imposition of restrictions on Palestinian movement, the removal of which, they claim, was one of the reasons the terrorists managed to carry out the attack in the first place.