The Russian Navy frigate Yaroslav Mudry visited Iran’s Chabahar port before taking part in the joint maneuvers with Iran and China. (Photo: Russia Defense Ministry)

Moscow (CNSNews.com) – At a time of simmering tensions between Washington and Tehran, Russia and China joined Iran in their first-ever three-way naval exercise in the Indian Ocean and the Gulf of Oman over the weekend.

“During naval maneuvers, Russian, Iranian and Chinese military sailors will work out episodes of screening and releasing a ship captured by pirates, joint maneuvering, assisting a ship in distress, and will also conduct anti-terrorist protection of ships and vessels in an unprotected raid,” the Russian Ministry of Defense said in a statement on Saturday.

Iranian officials celebrated the four-day exercise as a significant geopolitical statement, arguing that it showed that efforts by the United States to isolate the Islamic Republic had failed.

“The joint naval drill of Iran, China and Russia shows successful diplomacy of the Islamic Republic of Iran,” Major-General Abdolrahim Mousavi, commander of the Iranian army, told the Mehr news agency.

“This drill demonstrates the determination of countries that are seeking security in the region against those countries that are after creating insecurity,” Mousavi added.

Over the past year, the Gulf of Oman has emerged as a major flashpoint between the U.S. and Iran. Washington accused Tehran of orchestrating two attacks on oil tankers in the Gulf last summer.

In June, the Islamic Revolutionary Guard Corps (IRGC) shot down a U.S. surveillance drone over the Gulf of Oman. President Trump initially approved a retaliatory strike against Iran before he called it off last minute, citing the high risk of casualties.

Amid the mounting tensions with the U.S., Iran has moved to expand economic and military cooperation with Russia and China.

When President Hassan Rouhani introduced his “budget of resistance” against U.S. sanctions earlier this month, he emphasized that Tehran was in the process of finalizing a $5 billion investment deal with Moscow.

“We hope that $5 billion in capital will enter the country, either through plans that have already been finalized or which will be finalized next year,” Rouhani said.

China announced in September that it plans to invest $400 billion into Iran’s energy, transport and manufacturing sectors over the next 25 years, with the bulk of that investment potentially coming over the next five years.

Beyond holding joint naval drills with Iran, Russia and China are increasingly expected to sell the regime new fighter jets and tanks once the U.N. arms embargo against the country expires in October 2020.

Expiration of the ban comes as a result of the 2015 nuclear deal negotiated by the Obama administration. The Joint Comprehensive Plan of Action (JCPOA) states that the embargo will be lifted five years after the JCPOA’s adoption date, if Tehran abides by the agreement’s terms.

Meanwhile Russia and China are also strengthening ties with Saudi Arabia, Iran’s main regional rival. When President Vladimir Putin’s visited Saudi Arabia in October, Moscow and Riyadh signed $2 billion worth of deals. Russia also offered to sell the kingdom its S-400 air defense system.

China signed a $28 billion package of deals with Saudi Arabia during Crown Prince Mohammmad Bin Salman’s February visit to Beijing. Just last month, Beijing and Riyadh launched a three-week-long  joint naval exercise at the King Faisal Naval Base on the Red Sea.