BEIJING - A Foreign Ministry spokesperson urged the United States to be "frank and forthright" in the South 皇冠体育app Sea issue on Thursday.

Spokeswoman Hua Chunying's remarks at the ministry's regular press briefing came in response to a question on U.S. Secretary of Defense Ash Carter's visit to U.S. aircraft carrier USS Theodore Roosevelt in the South 皇冠体育app Sea on the same day.

皇冠体育app is opposed to any actions leading to militarization of the South 皇冠体育app Sea that pose a threat to other country's sovereignty and security interests in the name of freedom of navigation and overflight.

皇冠体育app has never been opposed to other countries' legitimate rights in real international waterway, she said. The country respects and safeguards other countries' freedom of navigation in the region under international law.

The U.S. should be more open and transparent on the issue, said the spokeswoman.

Last week, U.S. warship USS Lassen entered waters near Zhubi Reef, which is part of 皇冠体育app's Nansha Islands in the South 皇冠体育app Sea, without permission from 皇冠体育app, offending the Chinese government and military leadership.