Israel ramped up preparations Wednesday for a possible ground assault of Hamas targets in the Gaza Strip, amassing more troops at the border after it rebuffed a possible ceasefire.

Soldiers gathered at the edge of the densely-populated strip of land, along with dozens of tanks. Israel's government also approved the call-up of 9,000 reservists.

Overnight, Israeli Prime Minister Ehud Olmert had discussed a 48-hour truce proposal put forth by France with Foreign Minister Tzipi Livni and Defence Minister Ehud Barak.

The meeting ended with a rejection of the proposal.

Israel has rebuffed international pressure to impose a temporary halt of its offensive in Gaza, promising not to stop until Hamas guarantees they will no longer shoot rockets across the border.

Overnight, Prime Minister Ehud Olmert discussed a 48-hour truce proposal put forth by France with Foreign Minister Tzipi Livni and Defence Minister Ehud Barak.

The meeting ended with a rejection of the proposal.

"Giving Hamas a respite just to regroup, rearm is a mistake," Olmert spokesperson Mark Regev said. "The pressure on the Hamas military machine must continue."

CTV Middle East Bureau Chief Janis Mackey Frayer sat down with Livni in Sderot, a town in southern Israel hit hard by Hamas rockets, and asked her about Israel's objectives for the current military operation.

"When Israel is under attack we are going to retaliate, we are going to act back," Livni said. "I'm not going to exist as a government and say to my citizens, 'This is something you need to get used to' -- to be under attacks, even sporadic attacks, from the Gaza strip."

She said Israel wants to "change realities" in the Gaza Strip, meaning a regime change. However, she also said removing Hamas from power is not the purpose of the current military campaign, but that Israel hopes Palestinians will vote out the group.

"Now (Hamas) knows that when they target Israel, Israel will act back, and I mean with forces that are not a proportionate answer to rocket attacks," she said. "This should work once. And if they don't understand it, it's going to work in the future until they understand, and the population in Gaza understands, that Hamas is a problem for everybody."

Livni also dismissed criticism that Israeli's air strikes were carefully timed to coincide with the country's upcoming election to draw support from voters, and before Barack Obama -- who may be less supportive of Israel's tactics than George Bush -- takes office in the United States.

"It's not connected to elections or to timing, it's a question of a moment in which we can say, 'OK, reality has changed,'" she said.

Livni also said Israel is "not the aggressor in the conflict."

'Far away' from peace

Samah Sabawi, a spokesperson for the National Council on Canada-Arab Relations, said she was dismayed by that assertion.

"Israel has held, for 40 years, an illegal occupation of Palestinian land," Sabawi, who was born in the Gaza Strip, told CTV Newsnet on Wednesday. "That occupation itself is a form of aggression against the Palestinians.

She said the way Israel has treated the Palestinians -- building settlements in the territories, erecting walls -- is also a "great form of aggression, and until Israel starts to understand that, we're really far away from any kind of peaceful resolution."

The campaign, which will enter its sixth day, has so far killed about 400 people in the Gaza Strip and injured 1,600. Of the dead, at least 200 were uniformed Hamas members. According to the UN, 60 Palestinian civilians have also been killed.

Hamas is protesting a blockade enforced by Israel that has reduced the amount of food and medical supplies entering the country. Sabawi said her sister, a doctor working in Gaza, told her the hospitals have been flooded with casualties but lack enough resources to treat them.

"The situation is very dire," said Sabawi. "There is no hot water in the hospital. There is still no electricity, so the hospital is having to rely on generators to keep the lights on and keep the life-support machines running."

She also said that while some supplies are still reaching the hospital, staff have run out of medication to help burn victims.

"Because Israel destroyed the infrastructure and the fire department, there's a lot of fires going on from the bombings, and from people trying to find heat by burning wood and coal inside their homes," said Sabawi.

Attacks continue

Gabriella Shalev, Israel's ambassador to the UN, said the bombing campaign is the only way for Israel to bring about peace and security for Israelis targeted by rockets in the south.

"This is the right and the duty of every sovereign state to defend its own people so unless we get assurances and guarantees that Hamas will stop rocketing Israel, there will be no ceasefire," Shalev told CTV Newsnet on Wednesday.

By midday Wednesday, more than two dozen rockets and mortar shells had been fired on Israel, including five that struck Beersheba, a major southern Israeli city.

Militants have been able to extend their reach with better rockets, putting more than one-tenth of the Israeli population in danger.

Since the conflict began, four Israelis, including three civilians, have been killed by militant rocket fire.

Hamas spokesman Taher Nunu said Wednesday that the Gaza government is still functioning.

"What our people want is clear: an immediate stop to all kinds of aggression, the end of the siege by all means, the opening of all border crossings, and international guarantees that the occupation will not renew this terrorist war again," Nunu said in a statement.

The current crisis began roughly a week after a six-month truce between Israel and Hamas ended with a barrage of Hamas rocket fire. On Christmas day, 80 rockets were fired from Gaza into southern Israel.

Liberal Foreign Affairs Critic Bob Rae said Wednesday that Hamas needs to change the way it operates.

"Hamas has refused to recognize Israel and has rejected a ceasefire," Rae told CTV Newsnet. "It's absolutely crucial that Hamas change the way it behaves."

At the same time, Rae said everyone has to work with the Israelis to achieve a real ceasefire that Hamas will respect.

"We all have to be working with the Israeli government to make sure that the long term efforts at finding a peaceful solution are not lost sight of," he said.

Calls for an immediate ceasefire have also come from the Quartet -- the U.S., E.U., UN and Russia -- who joined together to attempt to broker a peace agreement in 2002.

"Israel says that at this stage there's no use in exploring band aid solutions to what they still see as a grave problem -- Hamas is still firing rockets from the Gaza Strip," Mackey Frayer said.

Although it has rejected the temporary ceasefire, Israel has agreed to allow 2,000 tons of food and medical supplies into Gaza Wednesday.

Shalev said Israel's borders were open all the time to allow aid into Gaza.

With files from The Associated Press