Major General Michael Edelstein, a veteran commander who is retired but is now working with the Israel Defence Forces' (IDF) Southern Command because of the war, said the attackers were "well trained, well equipped".

"You definitely can see evidence, we have evidence of Iranian involvement," he told a briefing with journalists on Monday after the Israeli military showed a nearly 45-minute compilation of footage from the 7 October carnage.

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The commander did not present any specific evidence of Iranian involvement beyond his testimony. He also declined to elaborate on what this evidence consisted of.

"I cannot elaborate too much, but you can understand what I mean. Not just about equipment but more than this."

His comments appear to go further than previous remarks by officials about the potential for an Iranian link to the bloodshed beyond the fact that Tehran has long offered military and financial support to the Palestinian militant group, which controls Gaza.

The assault, from the Palestinian territory into southern Israel, prompted Israeli leaders to declare war on Hamas.

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Asked whether the evidence that had been gathered meant the Hamas fighters had been trained abroad, the Israeli officer said: "I cannot elaborate. I am sorry.

"They built some training sites within Gaza and I can tell they act very professionally, unfortunately. In a very evil way.

"But this is the way they were trained to act."

The officer also said that documents found on the bodies of militants who were killed in the attack as well as with dozens of fighters who have been captured provide evidence of the specific instructions they were given.

"They came with orders to slaughter, burn citizens - not military personnel, simply citizens," Major General Edelstein said.

"They were looking for families in some of the kibbutz. They simply decided to burn families within their homes.

"On the other hand, they took hostages alive."

The Israeli government has published some of the documents it says were retrieved from the attackers.

They include one that was described as an "abduction manual" and another that was said to contain "operation plans".

Israel's president told Sky News on Sunday that Hamas militants had instructions on how to make chemical weapons.

Asked whether this meant the Palestinian group had a chemical weapons capability, Major General Edelstein said: "We are still looking for evidence about whether they have it or not.

"But the orders were there, as our president mentioned… orders were there.

"Orders were there on how many to kill, how to kill, how many to take as hostages. Orders were there to rape. It wasn't something that just happened... all was written and ordered."