"The attack was a breach of the Vienna agreement on diplomatic relations," said an official source at the Saudi Foreign Ministry.

Under the Vienna agreement, the hosting country has the responsibility to protect a foreign diplomatic mission, its staff and properties, the source pointed out.

"Saudi Arabia, which has suffered a lot from such attacks, emphasizes the danger posed by such attacks on all diplomatic missions without exception," the ministry official said.

Saudi Arabia stressed that all countries should comply with the Vienna agreement and other international charters that protect diplomatic missions.

Britain shut Iran's embassy in London and expelled all its staff on Wednesday, saying the storming of the British mission in Tehran on Tuesday could not have taken place without consent from Iranian authorities.

Foreign Secretary William Hague also said the British Embassy in Tehran had been closed and all staff evacuated following the attack by a crowd that ransacked offices and burned British flags in a protest over sanctions imposed by Britain on Tehran.