Iran said on Friday that dialogue with the U.S. over Tehran's nuclear program is "meaningless" following Israel's biggest-ever military strike against its longtime enemy, accusing Washington of supporting the attack.

"The other side (the U.S.) acted in a way that makes dialogue meaningless. You cannot claim to negotiate and at the same time divide work by allowing the Zionist regime (Israel) to target Iran's territory," Iran's Tasnim News Agency quoted Foreign Ministry spokesperson Esmaeil Baghaei as saying.

He added that Israel "succeeded in influencing" the diplomatic process and that the Israeli attack would not have happened without Washington's permission.

Iran had earlier accused the U.S. of being complicit in Israel's attacks, but Washington denied the allegation and told Tehran at the United Nations Security Council that it would be "wise" to negotiate over its nuclear program.

The sixth round of U.S.-Iran nuclear talks was scheduled for Sunday in Muscat, but it remained unclear whether it would proceed following the Israeli strikes.

Iran denies that its uranium enrichment program serves any purpose other than civilian use, rejecting Israeli allegations that it is secretly developing nuclear weapons.

U.S. President Donald Trump told Reuters that he and his team had known the Israeli attacks were coming but still saw room for an accord.