Iran launched more attacks on Israel and Gulf countries Monday, hours after Iranian state TV said Mojtaba Khamenei, son of the country’s late supreme leader and long considered a contender, had been named his successor.

Iran’s powerful paramilitary Revolutionary Guard answers to the supreme leader and the younger Khamenei will have a central say in the war strategy.

Oil prices skyrocketed Monday, leading to more worries that higher energy costs will fuel inflation and lead to less spending by U.S. consumers, the main engine of the economy. Tokyo’s benchmark Nikkei 225 index plunged as much as 7% in early Monday trading, while other Asian markets also tumbled.

Saudi Arabia sharpened its warnings to Iran, telling Tehran Monday it would be the “biggest loser” if it continues to attack Arab states. The Saudi statement came after a new drone attack apparently targeted its massive Shaybah oil field.

Here is the latest:

A Chinese envoy to the Middle East has called on all sides to stop their military actions and said attacks on non-military targets and civilians should be condemned.

Special Envoy Zhai Jun, meeting in Saudi Arabia with Foreign Minister Prince Faisal bin Farhan, said Sunday that the sovereignty, security and territorial integrity of all Gulf countries must not be violated, a Chinese Foreign Ministry statement said.

China is a major importer of oil and natural gas from the region.

Zhai also met Jassim Mohammed al-Budaiwi, the secretary-general of the Gulf Cooperation Council, the Foreign Ministry said.

South Korean President Lee Jae Myung on Monday warned that a steep rise in fuel prices could rattle the country’s economy and called on officials to accelerate efforts to diversify fuel routes away from the Strait of Hormuz.

Lee spoke at a Cabinet meeting after the country’s stock market opened with an 8% plunge, as concerns grew about how the spiraling war in the Middle East could affect an economy heavily dependent on trade and imported fuel.

Lee called on officials to aggressively use a 100 trillion won ($67 billion) market stabilization fund activated last week to reduce volatility in stock markets and strengthen monitoring of disruptive market activities, such as fuel price collusion or hoarding.

Foreign Minister Cho Hyun said Seoul was also negotiating with Gulf states to find alternative trade routes to reduce reliance on the Strait of Hormuz, including the possible use of alternative ports in the UAE.