Iran has told mediators Qatar and Oman that it is not open to negotiating a ceasefire while it is under Israeli attack, an official briefed on the communications told Reuters on Sunday, as the two foes launched fresh attacks and raised fears of a wider conflict, Reuters reported ​​​​​.

"The Iranians informed Qatari and Omani mediators that they will only pursue serious negotiations once Iran has completed its response to the Israeli pre-emptive strikes," said the official, who spoke on the condition of anonymity due to the sensitivity of the conflict.

Iran made "clear that it will not negotiate while under attack," the official said.

Israel launched a surprise attack on Iran on Friday morning that wiped out the top echelon of Iran's military command and damaged its nuclear sites, and says the campaign will continue to escalate in coming days, according to Reuters.

Iran has vowed to "open the gates of hell" in retaliation in what has emerged as the biggest ever confrontation between the longstanding enemies.