LONDON (AA) - UN experts condemned the military assaults on Iran and Lebanon by the US and Israel on Thursday as "flagrant violations of international law."

"The conflict risks engulfing the wider region in catastrophic armed violence and threatens to set yet another precedent of total impunity for some of the world’s strongest military powers," the experts said in a statement.

They stressed that the unprovoked attack by the US and Israel against Iran is "entirely illegal" under international law and constitutes an act of aggression.

"US and Israel should stop waging and expanding wars, and considering themselves as above international legality," the statement noted.

The experts expressed alarm at the US demand for Iran’s "unconditional surrender," warning that the move could lead to prolonged war and enormous human suffering.

They also condemned US demands for regime change, including declarations by US President Donald Trump that "he will choose the future leadership of Iran."

"No violations of human rights in Iran or elsewhere provide any legal or moral justification for an unwarranted interference with the sovereignty of a UN Member State and an illegal attack."

The statement urged all states to respect the rights of the Iranian people to self-determination, and to define and change their own political system free from foreign interference.

"Only the Iranian people can decide their own future, in full sovereignty, and in line with the principles of the rule of law and respect for human rights," they noted. "Any loss of life in an illegal war is a violation of the right to life.”

Calling for an independent investigation on specific attacks that could constitute grave violations of international humanitarian law, they cited the targeting of a girls school in Iran, in which at least 180 girls were killed, strikes on Iran’s oil refineries that caused acid rain, and attacks on a desalination plant.

They also condemned Israel’s escalation of hostilities in Lebanon, which could amount to an irresponsible act of aggression.

"The orders issued to the inhabitants of South Lebanon and southern Beirut to leave their homes are blatantly illegal," the statement underlined.

Regional escalation has flared up since Israel and the US launched a joint attack against Iran on Feb. 28 that has so far killed more than 1,300 victims, including then-Supreme Leader Ali Khamenei, and injured over 10,000, according to Iranian authorities.

Tehran retaliated with drone and missile strikes targeting Israel, Jordan, Iraq and Gulf countries that are home to US military assets.