"And they will be accused of participating, supporting terrorist acts against the civilian government," he said.

Israel last week detained scores of Hamas members in the West Bank, including eight ministers and more than 20 lawmakers and revoked the Jerusalem residency of four others in a new wave of air raids, and warning it would use all its power to free a soldier captured by militants a week ago.

Peres spoke after Israel struck at the heart of the Palestinian government on Sunday, dispatching helicopters which hit the Gaza office of the Hamas premier Ismail Haniya, setting the building ablaze.

However, he told CNN, Israel was not trying to kill the Hamas leader when it attacked the office. "It was attacked in the middle of the night, where no one would be in the office," he said.

"It was a clear warning," he said.

"So it was not an attempt on his life, but it was a clear warning to stop this double behaviour," he told CNN.

Peres also said Israel was not trying to topple the Hamas government.

"We are trying to topple down the policies of this so-called government, which are policies of terror.

"It is a government that was elected properly, but behaves like a terrorist organisation. So we didn't disturb the elections, but once we see the way they behave, we cannot consider them a government," he told the cable broadcaster.

Israeli Prime Minister Ehud Olmert vowed not to bow to "blackmail."

The armed wing of Hamas threatened resumed attacks inside Israel, sinking the region in a "sea of blood" if the Israeli offensive continued.

The chief Palestinian negotiator, Saeb Erakat, told CNN that Israeli airstrikes are only escalating the crisis.

"I'm afraid that every hour that passes we're going to lose the ability to solve the crisis," he said.

"Maybe the situation is out of hand now. I don't want to sound pessimistic, but I'm really afraid that every hour that passes, in this line of thinking, this line of action, I'm afraid that we're going to lose the ability to solve the crisis, diplomatically and politically," he told CNN.

He also said the Hamas-led government does not know where the soldier is.

"It's a needle in a haystack," he said of the ongoing search for the soldier in the densely-populated territory.

Palestinians cautioned that Egyptian-led mediation efforts were faltering to free the 19-year-old corporal, Gilad Shalit, captured on June 25.

Asked if more detentions of members of the Hamas government, which took office in March, were possible, Peres said answered in the affirmative.

"If there will be more people participating in acts of terror, yes," he told CNN.