Tehran (AFP) - Iran's supreme leader said Saudi Arabia is responsible for Thursday's stampede during the annual hajj in which 90 Iranians were among more than 700 Muslim pilgrims killed.

Laying the blame for the deaths on "improper measures" and "mismanagement," Ayatollah Ali Khamenei announced three days of mourning.

"The government of Saudi Arabia must accept the huge responsibility for this catastrophe," state news agency IRNA quoted Khamenei as saying, demanding that the causes of the accident "should not be overlooked".

On Wednesday, Khamenei had said Saudi Arabia bore a duty to protect all pilgrims. His remarks after the tragedy followed those of other Iranian officials who criticised the kingdom for failing to safeguard the ceremonies.

Deputy Foreign Minister Hossein Amir Abdollahian said earlier that Saudi's envoy to Tehran would be summoned to the foreign ministry over the stampede.

The head of Iran's hajj organisation, Said Ohadi, said bad decisions had led to the tragedy, the worst to hit the hajj in almost a quarter century.

Ohadi said that, for "unknown reasons," two paths had been closed off near the site of a symbolic stoning of the devil where the stampede occurred.

That left only three routes to the area where the stoning ceremony was held in Mina, about five kilometres (three miles) from Mecca, Ohadi said, asserting that such a step forced the crowd to form, resulting in the fatalities.

"This caused this tragic incident," he said on state television, later announcing the Iranian death toll on an evening news bulletin. A further 60 Iranians were injured.

"Today's events show mismanagement and lack of serious attention to the safety of pilgrims," said Ohadi. "There is no other explanation. The Saudi officials should be held accountable."

The names of the first 43 Iranians killed in the stampede were earlier read out in a sombre live broadcast in Tehran by a spokesman for the hajj organisation.

Saudi's civil defence service has said at least 717 people were killed and 863 hurt.

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Abdollahian also accused Saudi officials of "tactlessness" regarding safety at the hajj.

"We can in no way be indifferent to this irresponsible behaviour of Saudi Arabia. This will be dealt with through diplomatic channels," he said.

Saudi Health Minister Khaled al-Falih blamed undisciplined pilgrims for the tragedy, saying it could have been avoided if they had "followed instructions."

Iran has set up a special headquarters at the accident site to support its citizens there.

"Saudi Arabian officials are responsible for this incident and they should immediately endeavour to take effective measures for managing the existing crisis and providing full security for pilgrims," Abdollahian told the official IRNA news agency.