Rising tensions between Iran and Saudi Arabia were given fresh fuel Monday with both sides issuing tit-for-tat verbal volleys.
Regional rivals Saudi Arabia and Iran have been trading blows in an escalating war of words since Saturday following the former's move to execute prominent Shiite opposition cleric Sheikh Nimr al-Nimr.
Iran's Shiite leaders blasted the Sunni kingdom verbally, while protesters in Tehran stormed the Saudi Arabian embassy. Saudi Arabia responded by pulling its diplomats out of Iran, severing diplomatic ties and saying Iran's condemnation of the execution showed it supports terrorism.
Related: The Troubled History of Iran-Saudi Relations
World leaders — from the U.S., the United Nations, France and beyond — have urged all sides to avoid intensifying tensions or deepening sectarian divides.
Monday, though, showed no signs of respite from the ramped-up rhetoric and widening regional fallout.
Iran's First Vice President Eshaq Jahangiri called on Saudi Arabia to cease such "illogical, hasty and emotional" moves, according to the semi-official FARS news agency.
Foreign Ministry spokesman Hossein Jaberi Ansari said Saudi Arabia "thrives on prolonging tensions" and used the embassy incident "an excuse to fuel the tensions."
He struck back against Saudi claims that calls to protect the embassy were not immediately dealt with, saying that Iran had met its obligations to protect diplomatic missions.
His and other reactions came as further demonstrations were planned to protest al-Nimr's execution, including in Tehran.
While Shiite leaders continued voicing support for Iran, Sunnis were lining up to back Saudi Arabia.
Bahrain said Monday it too was severing diplomatic ties with Iran, giving Iranian diplomats 48 hours to leave the country. Bahrain also will be shuttering its diplomatic mission in Tehran, the foreign ministry added in a statement.
Iran and Saudi Arabia have long been at odds — the two previously cut diplomatic ties for several years in the late 1980s and have repeatedly accused each other of supporting terrorism.
However, the current spat comes amid broader regional instability — Iran and Saudi Arabia support opposing sides in the Syrian and Yemen wars — and put not just world leaders but investors on edge.
Oil prices jumped sharply higher on Monday, the first day of 2016 trading.