In 2014 US challenged maritime claims of 18 nations including

Dismissing allegations that it is singling out China in maritime disputes, the US today said in the last one year it has challenged the maritime territorial claims of 18 countries including some of friendly nations like India and Brazil.
"The fact is that the Department of Defense regularly conducts freedom of navigation operations around the world. In 2014, the Department of Defense challenged the excessive maritime claims of 18 different nations," White House Press Secretary Josh Earnest told reporters at his daily news briefing.
"These are nations as diverse as Iran, around the Strait of Hormuz. And other nations with them we have much warmer relations, nations like Nicaragua, India and Brazil," Earnest said in response to a question.

Asserting that China was not being singled out by the US, he said there are a variety of reasons for which the Department of Defense would carry out operations like this.
According to Pentagon, in a one year period between October 1, 2013 and September 30, 2014, the United States challenged multiple times India's "excessive maritime claims" that authorisation is required for any foreign military movement in its exclusive economic zone.
Other countries whose maritime territorial claims were challenged during this period included Argentina, Brazil, China, Ecuador, Indonesia, Iran, Libya, Malaysia, Maldives, Nicaragua, Oman, Philippines, South Korea, Taiwan, Venezuela and Vietnam.

Earnest's remarks came after he was asked that "there were reports that the US is planning to send a warship to some of the contested waters, potentially within 12 nautical miles of some of the island that were built there...China has said that they would not condone their territorial waters being breached, what your message would be to the Chinese."
"I think the (US) President delivered a pretty clear and resounding message in the rose garden when he was standing next to (Chinese) President Xi at the end of last month in which he declared, not for the first time, the United States will continue to fly, sail and operate anywhere in the world that international law allows," Earnest said.