China is again furious after the US sailed several warships through the heavily disputed waters in the South China Sea, military sources told Reuters. The move by the US has escalated tensions between both countries, already tense as the latest round of trade talks have fallen apart, and the signing of the phase one trade deal has likely been delayed.

The USS Gabrielle Giffords (LCS-10), an Independence-class littoral combat ship, on Wednesday sailed within 12 nautical miles of Mischief Reef, a militarized island in the South China Sea operated by China.

Then on Thursday, USS Wayne E. Meyer, an Arleigh Burke-class guided-missile destroyer, sailed through the Paracel islands in the South China Sea.

"These missions are based in the rule of law and demonstrate our commitment to upholding the rights, freedoms, and lawful uses of the sea and airspace guaranteed to all nations," Commander Reann Mommsen, a spokeswoman for the US Navy's Seventh Fleet, told Reuters.

China's People's Liberation Army shadowed the two US warships as they both transited through the disputed waters, and "warned them to leave." China's military warned the US has to stop sending warships near its militarized islands to "avoid the happening of any mishap."

"The US has kept sending naval vessels to stir up trouble in the South China Sea under the pretext of freedom of navigation," a statement from the Chinese military, with the Southern Theatre Command said. "We call on the US to stop such provocative acts to avoid the happening of any mishap."

Global Times China urges the US to stop provocations to avoid unforeseen incidents. The Chinese military is determined to safeguard the sovereignty of the country and maintain the peace and stability of the #SouthChinaSea no matter what tricks US vessels play: Southern Theater Command of #PLA

China's Foreign Ministry Geng Shuang, at a press briefing on Friday, told reporters, "the US actions severely damage China's sovereignty and safety, destroy the peace and stability in the South China Sea, and we express our resolute opposition."

Global Times The US' move to send two navy ships near the Nansha and Xisha Islands seriously undermines China's sovereignty and security interests, and peace and stability in the #SouthChinaSea. China has made solemn representations to the #US conveying strong opposition: Chinese FM

The US has increased freedom of navigation operations since the trade war began, attempting to counter China not just on economic fronts, but also on military ones. The latest freedom of navigation missions conducted by the US is coinciding with new reports this week, that the phase one trade deal between both countries has been delayed until 2020. The Trump administration is reportedly not willing to roll back tariffs for a deal that doesn't include intellectual property and technology transfer. This has caused renewed anxieties between Washington and Beijing.

As trade wars continue to be unresolved, it's becoming increasingly evident that military tensions between both countries are increasing as well.