The US State Department has issued a warning to China after its coast guard boats blocked the passage of Philippine resupply boats in the South China Sea. China and the Philippines are locked in a territorial dispute concerning that body of water.
Manila says two boats hired by the Philippine military were on their way to deliver supplies to troops stationed on a shoal in the Spratly Islands on Tuesday. It says three Chinese coast guard vessels blocked and used water cannon on the boats.
Beijing said that it was a legitimate response to what it described as an unapproved incursion into Chinese waters.
US State Department Spokesperson Ned Price said in a statement on Friday that Washington stood by its ally, the Philippines, amid an "escalation that directly threatens regional peace and stability."
Price also noted that an armed attack on Philippine public vessels in the South China Sea would invoke US mutual defense commitments under the US-Philippines Mutual Defense Treaty.
Washington has repeatedly said that it is illegal for China to claim the rights to control almost the entire South China Sea.