“This was not what the Vietnamese expected from a polite guest,” said Alexander L. Vuving, a Vietnam specialist at the Daniel K. Inouye Asia-Pacific Center for Security Studies in Hawaii.
“You can say both sides miscalculated,” he added. But another interpretation is that both countries are “very committed to showing the other their own resolve” on matters of territorial sovereignty.
The dispute happened during a visit to Hanoi this week by Gen. Fan Changlong of China. It was unclear what precisely roiled his meeting with Vietnamese officials, much less whether the general’s actions had been planned.
Analysts said he appeared to have been angry over Vietnam’s recent efforts to promote strategic cooperation with the United States and Japan. Prime Minister Nguyen Xuan Phuc recently visited those two countries in quick succession, and the Vietnamese and Japanese coast guards conducted joint drills in the South China Sea last week focused on preventing illegal fishing.
Another reason, analysts said, could be Vietnam’s apparent refusal to abandon oil and gas exploration in areas of the South China Sea that both it and Beijing claim.
Mr. Vuving said a specific source of the dispute may have been the so-called Blue Whale project, a gas-drilling venture in the South China Sea by Vietnam’s state oil company, PetroVietnam, and Exxon Mobil. The companies signed an agreement during a January trip to Hanoi by John Kerry, the secretary of the state at the time.
The drilling site, which is expected to produce gas for power generation by 2023, is close to the disputed Paracel Islands and near the “nine dash line” that shows expansive territorial claims on Chinese maps. Mr. Vuving said that China probably resents that Vietnam has formed a partnership with an American oil company, particularly one whose previous chief executive, Rex W. Tillerson, is Mr. Trump’s secretary of state.
The project appears to set a…