The Hamas rejected on Thursday a proposal put forth by Palestinian President Mahmoud Abbas to broker a cease-fire between the Islamist group and Israel.

Abbas' proposition came shortly after seven Palestinians were killed Thursday, including six militants, in an Israel Defense Forces operation in the northern Gaza Strip, as Gaza militants fired at least ten Qassam rockets and eight mortar shells at southern Israel.

Hamas spokesman Fawzi Barhoum described the proposal as "an extortion attempt" and said that Abbas allows Israel to continue its "massacre."

Meanwhile, the IDF released footage Thursday documenting its discovery of underground tunnels used by Gaza militants to conceal rocket launchers used to attack southern Israel.

The tunnels enable rocket squads to hide from IDF drones hovering above, and set timers on the Qassams which will then go off at a later time, making it much harder for Israel to target the militants.

According to security sources, the Palestinian militants received the operational know-how for the tunnels from Hezbollah.

Hamas in Iran: Expect terror wave in Israel

Israel can expect a wave of suicide bombings inside its 1967 borders, not just the West Bank, Hamas' representative in Iran said Wednesday. The announcement came as Palestinian militants from the Gaza Strip launched a barrage of Qassam rockets into Israel.

In a statement on Hamas' Internet site signed by the organization's delegate to Iran, Dr. Abu-Osama Abed Al-Ma'ati, the suicide attack that occurred earlier this week in Dimona was described as the beginning of a new wave of similar actions.

"We ceased to carry out these attack for a year, but the enemy persisted with its aggression and the violations to the cease-fire. The Dimona attack is a message. That message is that Iz al-Din al-Qassam has renewed the suicide attacks," the message said, referring to the Islamist organization's military wing.

Senior Hamas officials have said that the organization uses such online announcements to declare a change in tactics or policy. Showing consistency with the organization's line from Iran, Hamas' spokesmen in Gaza said the organization will continue to mount "resistance" and carry on with the suicide attacks.

Hamas official Sami Abu Zuhri defended the Dimona attack, which killed a 73-year-old Israeli woman. "There is no choice, no option for our people, but to resist the occupation and defend themselves by all possible means," he said.

Defense officials told Haaretz they view the announcement as a significant change because it comes from the organization's representative to Tehran - which has in recent weeks been pressuring Hamas to escalate hostilities against Israel.

In recent months, the Gaza Strip has seen the smuggling of Iranian Katyusha rockets. Since Hamas last month toppled the border fence separating the Gaza Strip from Egypt, Iranian-trained experts in terrorist activities have reentered the Strip, where Hamas has enjoyed sovereignty since it staged a bloody coup d'etat last June.

The renewal of suicide attacks in Israel as a matter of policy - as opposed to sporadic attempts by individual terrorists - fits in with the line the organization's military wing has been trying to promote.

Military-wing officials believe that the organization should escalate all hostilities against Israel, including suicide attacks, rocket launches and strikes at settlements in the West Bank.

Hamas has also stepped up its involvement in firing rockets into Israel over the past couple of days. In parallel with ordering militants to launch several Katyusha rockets at Ashkelon on Tuesday, Hamas' political officials have lowered their public profile. Defense officials in Jerusalem said this was done to minimize the risk of Hamas officials being killed in strikes by the IAF.

Despite the fresh upsurge in fighting, a poll released Wednesday showed Hamas gaining a jump in popularity after breaking down the border wall at Rafah on January 23. The move gave Gaza's quarantined people a 12-day taste of freedom before Egypt closed the breaches on Sunday.

While Hamas gains popularity and clout among Palestinians by breaking Israel's stranglehold on Gaza, even temporarily, Mahmoud Abbas' West Bank administration is strikebound - civil servants walked off the job Tuesday in a two-day protest against a new regulation aimed at forcing West Bank Palestinians to pay millions of dollars in back utility bills. Despite Hamas' increased popularity, Abbas' rival Fatah movement held on to its lead, according to an independent Palestinian poll published Wednesday.

The Palestinian Center for Policy and Survey Research said a survey it carried out between January 23 - the day of the border breach - and February 3 showed a 6-point rise in support for Hamas, to 39 percent compared with 33 percent in a poll carried out in mid-December. The latest survey showed support for Fatah falling to 46 percent from December's 52 percent.