After the horrific carnage in Gaza, when Israeli leaders knowingly and with malicious forethought dropped a one-ton bomb on a civilian apartment building, killing 15 people, 10 of them children, everyone expected a bloody revenge attack against Israelis. This came in the form of a bombing at Hebrew University, an Israeli enclave in the heart of occupied East Jerusalem.

This latest atrocity, which killed at least seven people, is no less horrible and worthy of condemnation by being expected. Hamas has claimed responsibility.

In past days, we have heard and read many reports that the Gaza bombing also torpedoed a promising initiative, in which Palestinian armed groups were to announce a moratorium on attacks against Israeli civilians.

Many, inside and outside Israel, have correctly blamed the government of Prime Minister Ariel Sharon for sabotaging this opportunity by going ahead with the Gaza attack.

It seems obvious to Palestinians, to many Israelis and to a growing number of others, that Sharon has no interest in a ceasefire and that he wants the violence to continue because violence is necessary to justify maintaining perpetual Israeli control of the West Bank.

But the opportunity was also missed by the Palestinian militant groups. If a halt to an attack on Israeli civilians was in the interests of the Palestinian people before the Gaza bombing, it was even more in their interests afterwards.

Leaving aside the immorality of blowing up children and non-combatants (whether they had the luck or misfortune – depending on how you see it - to be born Israeli or Palestinian), the whole world had recoiled in horror at the Israeli government's tactics which are almost indistinguishable from those of the 'terrorists' they claim to be fighting.

The leaders of the Palestinian groups that have in the past claimed responsibility for bomb attacks on Israeli civilians could and should have declared that the horror in Gaza would be the last atrocity, that they would no longer play Sharon's game. Instead they charged headlong into Sharon's trap, once again.

None of this ought to be construed as implying that there is any moral equivalence between the Palestinian struggle for liberation and the Israeli effort to impose a foreign military dictatorship on millions of people outside of Israel's borders. The inherent justice of the Palestinian cause is obvious, as is the deep immorality of the occupation.

Palestinians have a right, recognized by the entire world community, to resist this occupation. But resistance cannot and should not involve the deliberate murder of innocent civilians. The ends do not justify these means.Ali Abunimah is a Palestinian-American activist.