Secretary Of State John Kerry Says The United States Is "Deeply Concerned" That China Placed An Oil Rig In An Area Of The South China Sea Also Claimed By Vietnam. The Comments Come As Beijing's Army Chief Fang Fenguo Begins A Trip To The US As Part Of Efforts To Increase US - China Military Cooperation And Reduce Maritime Tensions. Chinese And Vietnamese Ships Have Rammed Into Each Other And Exchanged Water Cannon Fire On Several Occasions Since Beijing Set Up The State-Run Oil Rig Last Month. State Department Spokeswoman Jen Psaki Said Kerry Told Chinese Foreign Minister Wang Yi In A Phone Call The Move Was "Provocative And Aggressive," Those Tensions Were Noted In Public Remarks Monday By Secretary Of State Kerry In Washington During A Joint Appearance With His Singaporean Counterpart, Who Referred To The Relocation Of A State-Owned Chinese Oil Rig To The Paracel Islands Within Vietnam's Exclusive Economic Zone As " The Chinese Challenge" ... (Act / Kerry) In Response, China's Foreign Ministry Says Wang Urged Kerry To "Speak And Act Cautiously", Saying He Should Be Objective When Talking About China. China's State-Run Peoples Daily Says General Fang's Visit Is At The Invitation Of His American Counterpart, Joint Chiefs Of Staff Chairman General Martin Dempsey, Who Visted China In April 2013. The Peoples Daily Notes That The Visit Does Come Amid Heightened Tensions In The Asia-Pacific Region, But Said The Carefully Choreographed Schedule Will Highlight Both Countries Willingness For Close Military To Military Cooperation. Brad Glosserman. Executive Director Of The Hawaii-Based Pacific Forum Security Think Tank, Told VOA's Victor Beattie The US / China Military To Military Relationship Is Still In Its Early Stages, But Getting Stronger.