JERUSALEM - Prime Minister Ehud Olmert and his top security chiefs yesterday rejected calls for a massive ground offensive in the Gaza Strip after a renewal of rocket attacks on southern Israel by Hamas.

The decision gave a five-month cease-fire one last chance to succeed, despite repeated warnings by military officials that Hamas has been using the lull in fighting to smuggle large amounts of weapons into Gaza. But Israeli officials warned of "harsh steps" if the rockets kept falling.

In a separate development, the government's chief watchdog recommended opening a criminal investigation into a 2001 government transaction that involved Olmert before he became prime minister. The announcement further weakened the embattled Israeli leader ahead of a potentially explosive inquiry report next week on last year's war with Hezbollah guerrillas in Lebanon.

Olmert and Palestinian Authority President Mahmoud Abbas announced the Gaza truce in November, declaring an end to Palestinian rocket fire and Israeli attacks, including air strikes.

Some Palestinian groups have continued sporadic rocket attacks, but Hamas, which leads the Palestinian coalition government and which the United States and the European Union classify as a terrorist group, has kept its distance from the violence. According to the Israeli army, attackers have fired 230 homemade rockets at Israel since the truce, compared with about 600 launchings in the five months before the deal.

On Tuesday, Hamas said it fired dozens of rockets and mortar shells toward Israel to avenge deadly Israeli arrest raids in the West Bank, which is not covered by the truce. Israel said it counted a dozen strikes.

Nine Palestinians, including two civilians, were killed in fighting in the West Bank last weekend. Another was killed in a rare missile strike at a Gaza rocket squad.

With tensions rising, Olmert convened an emergency meeting yesterday of senior security officials to discuss a response.

Meeting participants said Israel would limit its activity to "pinpoint" operations aimed at halting rocket fire and other threats - effectively maintaining its policy of recent months.

Olmert's spokeswoman, Miri Eisin, said there would be no large-scale military raid in Gaza for the time being. "They decided to leave all options open," Eisin said.

Hamas has already threatened more attacks, with its spokesman saying Tuesday that it was ready to kidnap and kill more Israeli soldiers.

The head of the Egyptian security delegation, Col. Burhan Hamad, met yesterday with leaders of factions, including Hamas, Fatah and Islamic Jihad, and urged them to maintain the truce.

Senior intelligence officials, including the head of Israel's Shin Bet internal security service, have warned in recent months that Hamas - which has killed hundreds of Israelis in suicide bombings - is preparing for all-out battle. They say Hamas has used the lull to smuggle 30 tons of explosives into Gaza and has sent fighters to Iran for training.

Renewed fighting would be risky for both sides. Hamas has been trying to win international legitimacy to get economic sanctions lifted. Olmert has been weakened by the war in Lebanon and by corruption allegations.

Yesterday, state comptroller Micha Lindenstrauss contended in a lengthy report that Olmert used his influence to steer a government grant to a colleague while he was trade minister in 2001. Olmert also has been accused of shady real estate deals and improperly intervening in a bank-privatization deal. His office denied all wrongdoing.