GAZA CITY (CNN) -

An Egypt-backed cease-fire between Israel and Hamas fell apart Tuesday as rocket attacks from Gaza were again answered by Israeli airstrikes.

The rocket attacks from Hamas militants in Gaza never ceased, Israeli officials said. For its part, Israel refrained from airstrikes for about six hours before announcing it was resuming them.

A CNN crew witnessed at least five Israeli strikes just as the announcement was made.

"Hamas closed the diplomatic option. We woke up this morning in the hope there'd be a cease-fire and, as you reported, Israel restrained from all our activities, all action against terrorists in Gaza for a full six hours. We gave this cease-fire our full support," Mark Regev, spokesman for Prime Minister Benjamin Netanyahu told CNN's "The Situation Room with Wolf Blitzer."

"But Hamas said no to everyone. Hamas said no to the cease-fire, both in word and in deed," Regev said.

The faltering of the cease-fire attempt means there may be little hope of seeing an end to the near constant exchange of fire that has so far killed more than 190 Palestinians in Gaza.

The first fatality on the Israeli side was a man killed Monday after being hit by a mortar shell, Israeli Rescue Services said. He was an Israeli volunteer who was at the Erez border crossing to deliver food to soldiers.

Israeli leaders had agreed to the cease-fire, but from the outset warned it would be short-lived if the attacks from Gaza didn't stop.

The Israeli Security Cabinet met early Tuesday morning and decided to halt aerial strikes beginning at 9 a.m. (2 a.m. ET). It resumed strikes about six hours later, by 3 p.m. (8 a.m. ET).

The barrage from Gaza continued, with more than 140 rockets fired from there since early Tuesday -- or one rocket every six minutes -- according to the IDF.

"Hamas have decided to continue, and will pay the price for that decision," Netanyahu said Tuesday.

His Security Cabinet met again late in the day for emergency talks.

The Egyptian plan calls for all sides to cease hostilities in Gaza. It also calls for the opening of border crossings, once the security situation is stable, and for high-level talks among those involved.

"The achievement of the success of this Egyptian effort is a must for all of us," said Palestinian negotiator Saeb Erakat. "It's an interest for all of us, and if we allow things to deteriorate I think it's going to be a disaster all over."

He continued: "Failure is not an option here."

When the plan was announced, there was a split reaction from Hamas. Its military wing rejected any possibility of a cease-fire, while its political wing had said it was considering it.

Ismail Haneyya, deputy chairman of Hamas' political wing, said at the outset of the Egyptian efforts that there is a bigger issue than a cease-fire for Palestinians.

He said that what Palestinians really want is an end to the Israeli blockade on Gaza that is suffocating the daily lives of the 1.8 million Palestinians living there.

Haneyya, speaking on Hamas-owned Al Aqsa TV, also accused Israel of not freeing Palestinian prisoners from Israeli jails, as had been agreed to under an earlier truce. These, he said, are elements the Palestinians would like to see in a comprehensive cease-fire agreement.

Hamas spokesman Osama Hamdan later stressed that Hamas never received the proposal through political channels.

"We are still working with Egypt. We are still talking to other sides," he told CNN.

"I believe a proposal is supposed to be prepared after the sides agree on it. It's supposed to be published if two sides give agreement on it. You can't publish it in the media and then ask everyone to accept that or reject that."

Asked why Hamas won't stop firing rockets while talks are ongoing, the spokesman replied: "We are not the side who is killing the other side. We are are the side being killed."

Civilian casualties

The stakes are high and climbing.