MOSCOW, March 4 (Reuters) - Russia accused the United States on Wednesday of using an imaginary threat from Iran as a pretext to overthrow its constitutional order, and said Washington's calls for Iranians to seize power from their leaders were cynical and inhumane.

Foreign Ministry spokeswoman Maria Zakharova said the U.S. had used negotiations with Iran, which were taking place as recently as last week, as a cover to disguise a plan for regime change there.

GENEVA, March 4 (Reuters) - A committee of UN experts said on Wednesday it was "deeply disturbed" by the deaths of children amid escalating violence across the Middle East, particularly the bombing of a girls school in Iran.

The Shajareh Tayyebeh girls’ school in Minab in southern Iran was hit on Saturday, the first day of U.S. and Israeli attacks against the country. It killed 160 children, UN experts stated.

(Reporting by Olivia Le Poidevin, editing by Kirsti Knolle)

JOHANNESBURG, March 4 (Reuters) - South Africa is willing to play a mediating role in the Middle East conflict if asked, President Cyril Ramaphosa told local media on the sidelines of an energy conference in Cape Town.

"South Africa is always ready to play a contributing role, either in mediation or whatever. And if a gap opens or if we are asked, we always live up to our obligations," Ramaphosa said, according to comments broadcast on local broadcaster Newzroom Afrika.

By Alasdair Pal and Ryan Patrick Jones

SYDNEY/TORONTO, March 4 (Reuters) - Canadian Prime Minister Mark Carney said on Wednesday the ongoing conflict in the Middle East was a "failure" of the international order, and the United States had not consulted its allies before striking Iran.

U.S. and Israeli forces launched strikes against Iran on Saturday after negotiations over Tehran's nuclear programme stalled.

MADRID, March 4 (Reuters) - Spanish Prime Minister Pedro Sanchez on Wednesday doubled down on his opposition to the attack on Iran by the U.S. and Israel, warning that the conflict risked playing "Russian roulette" with the lives of millions.

Sanchez was responding after U.S. President Donald Trump threatened to cut trade with Madrid over its position on the conflict.

"This is how humanity's great disasters start ... You cannot play Russian roulette with destiny of millions," Sanchez said in a televised address to the nation.

Iran coach Marziyeh Jafari said Wednesday her team had "so much concern" about their families at home as war rages with players "fully disconnected" from them during the Women's Asian Cup.

The Iranian team are preparing to face host nation Australia on the Gold Coast Thursday after losing their opening game of the continental competition 3-0 to South Korea.

They will kick off once more with their homeland being bombarded by the United States and Israel.

Recycled images, video game footage passed off as missile strikes, and AI-generated combat visuals: the US-Israeli assault on Iran has unleashed a torrent of online disinformation that analysts are calling a war of narratives.

Since US and Israeli strikes over the weekend ignited a regional conflict, a parallel information war has erupted, with supporters on both sides flooding social media with falsehoods that often spread faster than the facts on the ground.

DUBAI, March 4 (Reuters) - 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 late Supreme Leader Ali Khamenei at Tehran’s Imam Khomeini Prayer Hall starting at 10 p.m. (1830 GMT).

Here are the latest main events related to the war in the Middle East:

- Explosions heard in Tehran: media -

Iranian news agency Tasnim reported that several explosions were heard in Tehran on Thursday morning.

It said the country had activated its defences in response.

- Iran launches missiles at Israel -

Iran launched a fresh round of missiles at Israel earlier Thursday, triggering alerts in several areas including Tel Aviv, according to the Israeli military and Tehran's state media.

By Maayan Lubell and Rami Ayyub

JERUSALEM, March 4, (Reuters) - Israeli Prime Minister Benjamin Netanyahu delivered on a career-long ambition to topple Iran's leadership, but his lockstep alignment with U.S. President Donald Trump faces a test as their joint military campaign threatens to drag on, with its goals potentially shifting in the coming weeks.