The United Nations Security Council on Monday condemned the attack on Saudi Arabia's embassy in Tehran following the execution of Shia cleric Sheikh Nimr al-Nimr on Saturday. 

United Nations Secretary-General Ban Ki-moon had phoned the foreign ministers of Saudi Arabia and Iran on Monday and urged them to ensure tensions in the region are not exacerbated. 

Ban expressed his disappointment to Saudi Arabia at the execution of the Shia cleric, and called on Iran to take necessary measures to protect diplomatic facilities in the country, according to the UN News Centre.

While condemning the attack on the Saudi embassy in Tehran, the UN chief told Saudi Foreign Minister Abel bin Ahmed Al-Jubeir that Riyadh's  decision to cut ties with Iran was "deeply worrying". 

Saudi Arabia on Monday said it was ending air traffic and trade links with Iran unless it "acts like a normal country", Reuters reported. It had already asked Iranian missions in the kingdom to leave by Tuesday. 

Iran's Ambassador and Permanent Representative to the UN Gholam Ali Khoshrou said in a letter to the UN secretary-general that Tehran regretted the incident at the embssay, which it said occured after "some protesters entered the Saudi embassy building and caused some damages to it despite widespread efforts by the law enforcement forces," according to Iranian news agency IRNA

He said Iran was making all efforts to arrest the attackers of the Saudi embassy. 

The execution of Sheikh Nimr al-Nimr, along with 46 others, in the biggest such mass execution in Saudi Arabia in over three decades, led to protests across Iran, and even in Lebanon and Bahrain. 

Bahrain, which is populated by a majority of Shias but governed by Sunni rulers, also joined Saudi Arabia in calling off diplomatic ties with Iran, while the United Arab Emirates downgraded its diplomatic representation to Iran.