Rating agency Moody’s warned on Monday that any sustained clashes could have global economic repercussions.

“A lasting conflict would have wide-ranging implications through broad economic and financial shock that significantly worsen operating and financing conditions,” Moody’s senior analyst Alexander Perjessy wrote in a note to clients Monday, CNBC reported.

“A protracted conflict would potentially have global repercussions, in particular through its effect on oil prices,” he added, CNBC said.

Iran’s supreme leader wept in grief with hundreds of thousands of mourners thronging Tehran’s streets on Monday for the funeral of military commander Qassem Soleimani, killed by a U.S. drone on the orders of U.S. President Donald Trump.

The killing of Soleimani, the architect of Iran’s drive to extend its influence across the Middle East, has stoked concern around the globe that a broader regional conflict could erupt, Reuters reported.

Trump has listed 52 Iranian targets, including cultural sites, that could be hit if Iran retaliates with attacks on Americans or U.S. assets.

General Esmail Ghaani, the new commander of the Quds Force, the elite unit of Iran’s Revolutionary Guards charged with overseas operations, promised to “continue martyr Soleimani’s cause as firmly as before with the help of God, and in return for his martyrdom we aim to rid the region of America”.

“God the Almighty has promised to take martyr Soleimani’s revenge,” he told state television. “Certainly, actions will be taken.”

Other political and military leaders have made similar, unspecific threats. Iran, which lies at the mouth of the key Gulf oil shipping route, has a range of proxy forces in the region through which it could act.

Democratic critics of the Republican president have said Trump was reckless in authorizing the strike. Republicans in the U.S. Congress have generally backed his move.

Trump also threatened sanctions against Iraq and said Baghdad would have to pay Washington for an air base in Iraq if U.S. troops were required to leave.

It was not clear if Washington had advised its allies of its plans before killing Soleimani. Britain, which also has troops in Iraq, said it understood why the United States had acted but called for a de-escalation to avoid war.

Saudi Arabia’s foreign minister said the region faced a “very dangerous moment”, while Turkey said it would work to stop Iraq becoming a “conflict zone for other, third-party countries”.

Oil prices climbed above $70 a barrel on concerns about an escalation.