WASHINGTON (TIP): The US Navy plans to conduct another passage near disputed islands in the South China Sea in early April, a source familiar with the plan said, the third in series of challenges that have drawn sharps rebukes from China. The exact timing of the exercise and which ship would travel inside a 12-nautical mile limit around a disputed island was not immediately clear.

The United States has conducted what it calls “freedom of navigation” exercises in recent months, sailing near disputed islands to underscore its right to navigate the seas. U.S. Navy officials have said they plan to conduct more and increasingly complex exercises in the future.

The USS Stennis carrier strike group is currently operating in the South China Sea. The next freedom of navigation exercise is unlikely to be conducted by a carrier like the Stennis, but rather by a smaller ship, the source said. Experts predict the next US challenge to the various claims in the South China Sea could occur near Mischief Reef, a feature claimed by the Philippines and which was submerged at high tide before China began a dredging project to turn it into an island in 2014.