Here are the latest updates:
Iran accused Saudi Arabia this morning of severing diplomatic ties and raising international tensions in the region in order to cover up its own domestic problems.
In a statement, a spokesperson for Iran's foreign ministry said the storming of the Saudi embassy in Tehran in the early hours of Sunday was being used as a pretext to escalate the crisis.
That incident came in response to Saudi Arabia's execution of 47 people on Saturday, including prominent Shia cleric Sheikh Nimr al-Nimr.
Iran's Hossein Jaberi Ansari said: "Iran... is committed to provide diplomatic security based on international conventions. But Saudi Arabia, which thrives on tensions, has used this incident as an excuse to fuel the tensions."
Meanwhile, the British security services said they were investigating a video released by the Isis militant group on Sunday which claimed to show the execution of five UK spies.
The footage included a "message" for David Cameron and a threat to wage war on Britain, and featured a militant and young child speaking in British accents.
