The Chinese navy is preparing some of its most modern ships for long duration operations. Recently, a flotilla of landing ships, destroyers and frigates, made a ten day cruise into the East China Sea. Chinese warships have also been seen practicing underway replenishment from a new replenishment ship. The Chinese have been working hard on how to use their new supply ships. Underway replenishment means transferring fuel and other supplies to moving ships, and the Chinese were seen moving fuel to two ships at once. This requires skill and practice, and the Chinese are out there obtaining both. These exercises appear to be only for a small number of ships. But this force would be sufficient for China to enforce it's recent announcement that it would forbid other countries from occupying, or building on, the many small islands in the East China Sea that are claimed by several countries.
These disputed areas include the Spratly Islands, which sprawl across some 410,000 square kilometers of the South China Sea. Set amid some of the world's most productive fishing grounds, the islands are believed to have enormous oil and gas reserves. Several nations have overlapping claims on the islands, including China, Malaysia, the Philippines, Taiwan, and Vietnam. Brunei has established a fishing zone in the area, but has made no territorial claims. From time to time there have been small-scale confrontations and the occasional clash between some of these countries over the ownership of the islands.
Then there are the Diaoyu/Senkakus Islands, which are basically a group of uninhabited islets in the East China Sea. Known to China and Taiwan as the Diaoyu islands and to Japan as the Senkakus, the area is rich in fish. As with the Spratlys, the area is reputed to have extensive natural gas reserves.
There are also the Paracel islands, which China occupies. Taiwan and Vietnam also claim ownership, but are not likely to attempt the use of force.