Iranians will bid farewell to late Supreme Leader Ayatollah Ali Khamenei at a ceremony in Tehran late on Wednesday, a senior Iranian official told state media.

Hojjatoleslam Mahmoudi, head of Iran's Islamic Propagation Council, said the farewell ceremony would continue for three days, and the funeral procession will be announced later.

The official said the public will be able to pay their respects to the body of Khamenei at Tehran's Imam Khomeini Prayer Hall starting at 10 p.m.

"The Mosalla [prayer hall] will be receiving visitors, and the dear people can attend and take part in the farewell ceremony and mark a strong presence once again," he said in comments carried by Iranian media.

Khamenei, who based his iron rule of Iran on hostility to the United States and Israel, was killed on Saturday, aged 86, in airstrikes by Israel and the U.S., according to Iranian state media.