A、Because Israeli troops had already counterattacked the Palestinian militants properly, killing two and injuring one. B、Because

Israel massed troops and tanks at the Gaza frontier and gave a free hand to security forces to stop Palestinian cross-border rocket salvoes on Sunday, but suggested it would delay a major escalation of violence.
   Palestinian President Mahmoud Abbas accused Israel of undermining his efforts to cahn the violence but vowed in remarks to reporters to do "all we can" to prevent further rocketing.
   The worst surge in bloodshed since a truce was agreed in February has threatened to hamper Israel’s withdrawal from Jewish settlements in occupied Gaza, starting next month, and amplified doubts over prospects for peacemaking  ....
   Prime Minister Ariel Sharon said he had instructed the army "to act without limitation to stop the strikes on Israeli communities" after rocket and mortar salvoes.
   But Sharon later hinted Israel would not be quick to launch a major incursion into Gaza, telling his cabinet he would "weigh our response" to further truce violations.
   Israeli political sources said a new Israeli offensive into the occupied territory was unlikely before Secretary of State Condoleezza Rice visits lat er this week to try to salvage the crumbling ceasefire
   Six more Israelis were injured in rocket and mortar barrages on Sun day.
   In  the  southern  Gaza  Strip,  Israel  killed  Saeed  Seyam,  a commander of Hamas, a group bent on Israel’s destruction and behind
much of the rocket fire, with a shot from a settlement. The army called it part of a revived assassination policy.
   Israel said its soldiers also killed a gunman nearing a settlement in central Gaza.
   In northern Gaza, an Israeli aircraft fired missiles at a car carrying three Hamas militants leaving a site in Belt Lahiya used to fire rockets at Jewish settlements, witnesses said. The militants jumped out but one was wounded by shrapnel.