Jan. 3 (Bloomberg) -- Israeli forces moved into the Gaza Strip, broadening an eight-day offensive against Hamas aimed at forcing the Islamist Palestinian group to stop firing rockets at the Jewish state’s southern cities.

“A few hours ago Israeli forces went into Gaza as part of the ongoing operation there. From the beginning, I said that the operation would be broadened as necessary, and now it is necessary,” Israeli Defense Minister Ehud Barak said in a televised news conference from Tel Aviv.

“Israeli forces plan -- inter alia -- to take control of the launch areas from which most of the missiles that have hit Sderot, Ashkelon and Ashdod in recent weeks and months have been fired,” according to an e-mailed statement from Israeli Prime Minister Ehud Olmert’s office.

The ground offensive is likely to increase casualties on both sides, with Israel running the risk of finding itself in a quagmire with no easy exit strategy and facing increased international pressure to call a cease-fire. The operation comes after Foreign Minister Tzipi Livni said on Channel Two that Israel was “determined” to meet the goals of the operation against Hamas.

“The objective of this stage is to destroy the terrorist infrastructure of the Hamas in the area of operation,” the Israeli army said in an e-mailed statement.

‘High Price’

Hamas’s armed wing said that Israel will pay a “high price” for its ground offensive. “The Zionist enemy is getting very close to the trap we have prepared for them,” the group said in a message sent to journalists by text message.

“We will fight till our last breath, your invasion of Gaza will not be a cake walk, Gaza will be your cemetery and you have no choice but to end the aggression and lift the blockade,” Hamas spokesman Ismail Radwan said in a statement broadcast on Al-Jazeera television.

Hamas said it planned to send “dozens” of suicide bombers to Israeli cities and kidnap more Israeli soldiers. Corporal Gilad Shalit has been held captive in Gaza for more than two years.

The Israeli government cleared the way today for the call-up of tens of thousands of reservists, expanding an earlier approval for the drafting of 7,000 soldiers in the reserves, according to a statement on Olmert’s Web site.

Draft Notices

The army said that this evening it issued “many” draft notices to reserve soldiers in combat units.

“This will not be easy. It will not be short,” Barak said. He warned the Shiite Muslim Hezbollah in south Lebanon, with which Israel fought a monthlong war in 2006, that Israel would retaliate if fired on.

“We are also watching the northern border. We hope that the northern border will stay quiet but we are ready and prepared for any possibility,” he said.

Hezbollah leader Sheik Hassan Nasrallah urged Hamas to inflict maximum losses on the Israeli forces in remarks to the militia’s Al-Manar television.

“Our brothers in the resistance in Palestine know that it is by inflicting the biggest possible losses on the Israeli enemy during the ground confrontation that they will win the battle,” Hassan said.

Israel began the campaign to halt rocket attacks by Islamic militants after a six-month cease-fire with Hamas expired Dec. 19. Militants launched more than 3,000 rockets and mortar shells at Israel since the beginning of 2008, the Israeli army said. Hamas refused to renew the cease-fire because it said Israel had not eased its economic blockade of Gaza and launched 70 rockets at Israel the day before it ended.

Infantry, Tanks

More than 435 Palestinians have been killed and 2,285 wounded since Israel started its aerial campaign on Dec. 27, according to the Palestinian Authority’s emergency services office in Gaza City. Four Israelis have died in the violence.

Infantry, tanks, engineering forces, artillery and intelligence units are taking part in the ground offensive, backed by the air force, navy and other security agencies, the army said. A naval blockade was imposed at 20 nautical miles off the Gaza shore, it added.

The Israeli government rejected Dec. 31 a French proposal for a temporary cease-fire with Hamas, saying it would be a “mistake” to give the movement time to rearm and regroup.

Hamas denies Israel’s right to exist and condemns Palestinian Authority President Mahmoud Abbas as a stooge for conducting peace talks over the past year. Hamas seized control of Gaza in 2007 after a brief power-sharing arrangement with Abbas, of the rival Fatah movement. The Palestinian Authority said it was halting peace talks because of Israel’s offensive.

The strikes on Gaza, where about 1.4 million people live and unemployment has soared to 49 percent, have triggered global calls for restraint.

To contact the reporters on this story: Gwen Ackerman in Jerusalem at gackermanbloomberg.net; Saud Abu Ramadan in Gaza City through the Tel Aviv newsroomt .

Last Updated: January 3, 2009 15:48 EST