China, Iran, and Russia carried out joint naval exercises in the Middle East on Tuesday, demonstrating their military strength in a region already tense over Iran’s growing nuclear program. The situation has been further complicated by threats from Yemen’s Houthi rebels to launch new attacks on ships.

The exercises, named Maritime Security Belt 2025, were held in the Gulf of Oman, close to the Strait of Hormuz, a vital passage through which about 20% of the world’s traded crude oil flows. This area has previously witnessed Iran seizing commercial vessels and allegedly carrying out attacks, particularly after the U.S., under President Donald Trump, withdrew from Tehran’s nuclear agreement with world powers.

This marks the fifth consecutive year these three nations have conducted joint drills. The exercise may have contributed to a warning issued late Monday by the British military’s United Kingdom Maritime Trade Operations Centre. The alert highlighted GPS signal disruptions in the strait, which lasted several hours and forced ship crews to rely on alternative navigation systems.

“This was likely GPS jamming to reduce the targeting capability of drones and missiles,” noted an intelligence analyst named Shaun Robertson at the EOS Risk Group. “However, electronic navigation system interference has been reported in this region previously during periods of increased tension and military exercises.”

Russia’s Defense Ministry sent the corvettes Rezky and Hero of the Russian Federation, Aldar Tsydenzhapov and the tanker Pechenega to participate in the naval drill. Meanwhile, China’s Defense Ministry deployed the guided-missile destroyer Baotou and the supply ship Gaoyouhu. However, neither country disclosed the number of personnel involved in the exercises. Unlike the U.S. and its allies, China and Russia do not regularly patrol the Middle East, despite its waterways being critical for global energy supplies. Instead, they largely leave that responsibility to Western nations, with the U.S. Navy’s Bahrain-based 5th Fleet playing a leading role.

Several countries, including Azerbaijan, Iraq, Kazakhstan, Oman, Pakistan, Qatar, South Africa, Sri Lanka and the UAE, sent observers to monitor the drills. At the same time, the U.S. was also likely keeping an eye on the situation. Both China and Russia have strong ties with Iran. China continues to buy Iranian crude oil, often at a discounted rate due to Western sanctions and remains one of Iran’s key trade partners. Russia, on the other hand, has relied on Iran for bomb-carrying drones used in its ongoing war in Ukraine.

The joint naval drills were a significant event for Iran’s state-run television, which broadcasted footage of live-fire exercises during nighttime operations and sailors operating deck guns on a vessel. These exercises followed months of Iranian military drills that were conducted in response to a direct Israeli attack on Iran, targeting its air defences and ballistic missile sites. Although Tehran downplayed the attack, it caused concern among the Iranian public. Meanwhile, Israeli operations, including assassinations and strikes, have severely weakened Iran’s so-called “Axis of Resistance”, a network of militant groups aligned with the Islamic Republic.

The situation worsened for Iran when Syrian President Bashar Assad was overthrown in December, further diminishing its influence in the region. At the same time, Iran has been stockpiling increasing amounts of uranium enriched to near weapons-grade levels, a move typically associated with nuclear-armed nations. While Tehran insists its nuclear program is for peaceful purposes, its officials have been making more frequent threats about pursuing nuclear weapons.

Both Israel and the U.S. have warned that they will not allow Iran to develop a nuclear weapon, hinting that military action against Tehran’s nuclear program remains an option. However, just last week, former U.S. President Donald Trump reportedly sent a letter to Iran’s Supreme Leader, Ali Khamenei, proposing a new nuclear deal. Iran, however, claims it has not received any such letter but still responded with several statements regarding the matter. Meanwhile, as a fragile ceasefire continues between Israel and Hamas in Gaza, Yemen’s Houthi rebels have announced they are resuming attacks on ships in the Red Sea, the Gulf of Aden, and the Bab el-Mandeb Strait, a key maritime route connecting the two waters.

On Friday, the Houthis’ leader, Abdul-Malik al-Houthi, warned that if Israel did not allow aid into Gaza, they would resume attacks on Israel-linked ships within four days. As the deadline passed on Tuesday, the Houthis declared a renewed ban on Israeli vessels in waters near Yemen. Although no fresh attacks have been reported, the situation has heightened concerns among shipping companies. In previous attacks, the Houthis have targeted more than 100 merchant ships with missiles and drones, sinking two vessels and killing four sailors.