Israel has said the international community should have grave concerns about the election of Iran's new president-elect, Ebrahim Raisi.

A spokesman for Israel's foreign ministry, Lior Haiat, said Mr Raisi is Iran's most extremist president yet.

He also warned the new leader will increase Iran's nuclear activities.

Ebrahim Raisi was declared the winner of Iran's presidential election on Saturday, in a race that was widely seen as being designed to favour him.

Mr Raisi, who will be inaugurated in August, is Iran's top judge and holds ultra-conservative views. He is under US sanctions and has been linked to past executions of political prisoners.

In a statement following his victory, he promised to strengthen public trust in the government, and be a leader for the entire nation.

"I will form a hard-working, revolutionary and anti-corruption government," state media quoted him as saying.