Tehran has threatened “serious consequences” for South Korea if it interferes in the US-Israel war on Iran. The warning comes amid reports that Seoul is mulling contributing to the US naval blockade of the Strait of Hormuz passage, which has hampered Iran’s oil exports. In a statement posted on X on Monday, Ministry of Foreign Affairs spokesman Esmaeil Baghaei said Iran and South Korea had more than 64 years of diplomatic relations based on mutual respect and that Tehran values that friendship. However, if South Korea joins the United States in its military actions against Iran at a time when the country is defending itself from what he called US aggression and “war crimes against women and children”, then there will be consequences, he warned.
Baghaei threatened that Iran would regard any military presence or participation in operations by another country in the Gulf and the Strait of Hormuz “would inevitably be regarded as direct support for the aggressor and would have serious consequences”. “No sovereign and responsible country should succumb to US pressure and intimidation and become complicit in acts of aggression and horrific crimes against the great Iranian nation,” he added. Seoul did not respond directly, but a Ministry of Foreign Affairs statement on Monday said it is communicating with the international community over the situation in the passageway. Here’s what we know about how South Korea is getting roped in: Seoul, a close ally of Washington, has been under pressure from US President Donald Trump. The issues began in mid-August, when Trump revealed in an interview, and later online, that he had spoken to South Korean President Lee Jae Myung and asked that Seoul give “a little hand” in the war on Iran.
According to media reports, the two leaders had spoken over the phone on May 17. Seoul said, “No, thanks!”, according to Trump’s message on social media. However, as South Korea now knows, saying no to Trump has repercussions. On August 16, Trump announced that the US would significantly scale back joint military drills it holds annually with South Korea – the evening before they were scheduled to begin.
The Ulchi Freedom Shield (UFS) exercises are meant to sharpen Seoul’s readiness in case of a North Korean attack. They usually last for more than 11 days but were reduced to five. In a post on his Truth Social site, Trump claimed the drills were “costly” and that they send a “hostile” signal to North Korean leader Kim Jong Un, with whom he is trying to build a relationship. South Korean Foreign Minister Cho Hyun said in parliament there was no warning from the US.
Trump also questioned why South Korea would refuse his request when thousands of US soldiers are stationed on the Korean Peninsula. The US also cancelled another military exercise scheduled for September, although South Korea’s military revealed it received a notification much earlier in June, with Washington citing constraints due to the war on Iran. President Lee, a liberal who pushes for a dialled-down defence posture, has opted to negotiate. His office earlier released statements saying it hopes for “meaningful dialogue” with Trump.
South Korea’s Yonhap news agency reported on Monday that Washington has, however, “ratcheted up pressure” on Seoul. On Friday, a South Korean presidential official told Yonhap that Seoul could consider a military contribution to international measures seeking to free up navigation in the passageway as long as it does not affect the country’s defence readiness. South Korea is looking at various options, the official said, including possible cooperation with France, the United Kingdom and other allies on sending noncombat and search-and-rescue forces. The South Korean military has also started reviewing assets and troops that could be deployed, including maritime patrol aircraft, explosive ordnance disposal teams and unmanned mine detection and clearing systems, he added.
Such a move would be unpopular. The opposition has spoken out against a possible deployment, as have some within Lee’s ruling Democratic Party. Many South Koreans have also protested against the US-Israel war on Iran. South Korea became one of the US’s closest allies after Washington backed Seoul against Pyongyang in the Korean War of 1950.
The US supported Seoul’s economic and military growth in the years after. Under a treaty, some 29,000 US soldiers have been stationed permanently on the Korean Peninsula since the end of the war. Seoul has also relied on US defence might to deter nuclear-armed North Korea. In return, South Korea supported several US wars, including the Iraq War, and is designated an important non-NATO ally.
In 2025, however, Washington imposed a 25 percent tariff on the country, testing relations. Seoul opted to negotiate rather than retaliate, leading the US to lower tariffs to 15 percent. Many South Koreans were also alarmed after hundreds of South Koreans were arrested in Immigration and Customs Enforcement (ICE) raids on a Hyundai plant in Georgia in September 2025. Last October, Trump travelled to Seoul in a historic state visit, and earlier this year, President Lee visited the US.
Lee is also trying to resume dialogue between Washington and Pyongyang. South Korea is facing an economic crisis. The country relies on the Gulf supplies via the Strait of Hormuz for 60 to 70 percent of crude imports, meaning supply is being severely hit. The war has led to soaring inflation, causing the Korean won to fall to a 17-year low.
Seoul therefore has an interest in freeing up the strait. However, under Korean law, the government will require parliament’s approval before a military deployment, although some governing party members could oppose it.
