As IDF chief tells announced that Israel is fighting Iran alone, China, Iran and Russia have scheduled joint naval drills in the Indian Ocean and Sea of Oman starting on Friday and ending on Monday, China’s defense ministry said on Thursday, Reuters reported.

China’s Xining guided missile destroyer will participate in the drills, which are meant to deepen cooperation between the three countries’ navies, ministry spokesman Wu Qian said, adding that it was a “normal military exchange” in line with international law.

The Sea of Oman is a critical waterway as it connects to the Strait of Hormuz, through which about a fifth of the world’s oil passes, the report noted. This comes as tensions between Iran and the United States and Israel have risen throughout the year, especially since U.S. President Donald Trump pulled the United States out of the 2015 Iran nuclear deal with world powers and increased sanctions on the country.

The United States has planned to lead a naval mission in the Gulf since alleged Iranian attacks on vessels earlier this year.

In September, the United States and Saudi Arabia blamed an attack on Saudi oil facilities on Tehran, but Iran denied the allegations.