DUBAI (Reuters) -Tehran was not involved in the militant Hamas group's weekend attack on Israel, Iran's top authority Ayatollah Ali Khamenei said on Tuesday, but hailed what he called Israel's "irreparable" military and intelligence defeat.

"We kiss the hands of those who planned the attack on the Zionist regime," said Khamenei, who was wearing a Palestinian scarf, in his first televised speech since the attack.

"This destructive earthquake (Hamas' attack) has destroyed some critical structures (in Israel) which will not be repaired easily ... The Zionist regime's own actions are to blame for this disaster," said Khamenei.

Israel has long accused Iran's clerical rulers of stoking violence by supplying arms to Hamas. Tehran, which does not recognize Israel, says it gives moral and financial support to the group, which controls the Gaza Strip.

Backing the Palestinian cause has been a pillar of the Islamic Republic since the 1979 revolution and a way the Shi'ite-dominated country has fashioned itself as a leader of the Muslim world.

The United States said on Monday Iran was complicit in Hamas' assault on Israel, but added it had no intelligence or evidence supporting this assertion. The top U.S. general on Monday warned Iran not to get involved in the crisis, saying he did not want the conflict to the broaden.

Israel said earlier on Tuesday it had re-established control over the Gaza border and was planting mines where militants had toppled the barrier during their bloody weekend assault, after another night of relentless Israeli air raids on the enclave.

Khamenei said an attack on Gaza would "unleash a much heavier torrent of anger'.

"The occupying regime seeks to portray itself as a victim to escalate its crimes further ... this is a misguided calculation ... It will result in even greater disaster," Khamenei said.

Israeli TV channels said the death toll from the Hamas attack had climbed to 900, with at least 2,600 injured. Gaza's Health Ministry said at least 687 Palestinians were killed and 3,726 wounded in Israeli air strikes on the blockaded enclave since Saturday.

(Additional reporting Elwely Elwelly in Dubai,Writing by Parisa Hafezi; Editing by Andrew Heavens, Gareth Jones and Bernadette Baum)