Hamas won't remain idle "in the face of a Zionist escalation" in the Gaza Strip.
"We will defend, with our utmost force, any new Zionist aggression against the Gaza Strip," the group said in a statement on Sunday announcing that it had reached agreement with other Palestinian groups to stop firing rockets and missiles at Israel, "to preserve the internal front."
The armed wing of Hamas, Izzadin Kassam, said that the decision "was not taken out of weakness, but out of a keenness to preserve the internal front and national interests of the Palestinians."
The Hamas interior minister, Fathi Hammad, said his government would not take any measures to stop the attacks on Israel unless all the Palestinian groups reached an agreement to declare a cease-fire.
He said that the Palestinian groups, including Hamas, maintained the right to respond if and when Israel invades the Gaza Strip again.
Sources close to Hamas said that the latest decision to stop the attacks on Israel was apparently linked to reports about significant progress in secret negotiations to secure the release of IDF soldier Gilad Schalit.
The Hamas minister would neither confirm nor deny the reports.
However, he said that Hamas has instructed all its spokesmen and representatives to refrain from making public statements about the negotiations.
The IAF bombed targets belonging to the Islamist organization overnight Saturday in response to a Kassam attack over the weekend.
Two weapons-manufacturing facilities in the northern and central Gaza Strip, and one smuggling tunnel in the Rafah area near Sinai, were hit in the IAF raids, the army said.
Palestinian sources said six people were wounded in the strikes.
According to the IDF Spokesman's Office, the attack came in response to a Kassam fired at an Israeli civilian area earlier on Saturday. The rocket hit the Sha'ar Hanegev region, causing no casualties or damage.
The IDF said it would not tolerate any attacks by terrorist organizations against Israel and its citizens, adding that nearly 270 rockets and mortar shells had been fired at the South since the end of Operation Cast Lead on January 18, in comparison to the more than 3,300 rockets and shells fired in the year before the offensive. The last month had seen approximately 15 rockets and mortar shells fired at Israel from Gaza, said the army.
Despite Hamas's announcement that Palestinian groups have agreed to halt the attacks on Israel, three factions in the Gaza Strip said they were not aware of any agreement in this regard.
The Popular Front for the Liberation of Palestine strongly denied that its members were part of a cease-fire agreement. The group's armed wing, the Abu Ali Mutapha Brigades, said it remained committed to the "option of confrontation and resistance against the occupation in all forms."
Islamic Jihad also denied that it had agreed to stop attacks on Israel. A spokesman for the organization in the Gaza Strip said he did not know of any Egyptian-brokered cease-fire agreement.
The spokesman said that it was inconceivable that the Palestinians would agree to stop the "resistance" while Israel was continuing its "aggression" against the Palestinians.
"We stick to our right to confront the occupiers for as long as they are on our Palestinian lands," he said. "We won't accept the principle of security for security. The enemy will leave only through resistance."
Jerusalem Post staff contributed to this report.