Donald Trump
Donald TrumpReuters

After China offered to return the US underwater naval drone it seized on Friday in the South China Sea, President-elect Donald Trump asked the Chinese government to "keep it".

The US on Friday had demanded that China should immediately release the naval drone "unlawfully" seized by the mainland in international waters. The incident hit a new point of tension between the US and Chinese military forces in the disputed waters. Pentagon Press Secretary Peter Cook said that China must comply with all of its obligations under international law and return the drone taken by it.

Trump, however, was in not in a mood to demand the device back; he instead tweeted that China should keep the drone they "stole" from the US. "We should tell China that we don't want the drone they stole back.- let them keep it!" Trump tweeted on Saturday evening.

Trump's interjection in the incident could further complicate the worsening relationship between the US and Chinese militaries in the South China Sea.

"Using appropriate government-to-government channels, the Department of Defence has called upon China to immediately return an unmanned underwater vehicle (UUV) that China unlawfully seized on December 15 in the South China Sea while it was being recovered by a US Navy oceanographic survey ship," Cook said.

"We have registered our objection to China's unlawful seizure of a US unmanned underwater vehicle operating in international waters in the South China Sea. Through direct engagement with Chinese authorities, we have secured an understanding that the Chinese will return the [drone] to the United States," Cook added.

Cook also added that the USNS Bowditch (T-AGS 62) and the UUV system is used around the world to assimilate military oceanographic information like salinity, water temperature and sound speed. He said that the UUV system was conducting routine operations in accordance with the international law around 50 nautical miles northwest of Subic Bay, Philippines, when a Chinese Navy PRC DALANG III-Class ship (ASR-510) launched a small boat and retrieved the UUV.

China's Ministry of Defense on Saturday said they had agreed to return the US naval drone in an "appropriate" manner; however, they did not specify what they meant by their statement.

A spokesman for the Ministry of Defence, Yang Yujun, said in a statement that China seized the drone "in order to prevent the device from harming the navigation safety and safety of the ship."

The South China Sea dispute involves island and maritime claims in the region among several sovereign states around the area, including the People's Republic of China, the Republic of China (Taiwan), Malaysia, the Republic of the Philippines, the Nation of Brunei and the Socialist Republic of Vietnam. Many international non-claimant nations, however, want the South China Sea to remain as international waters considering a high proportion of the world's trade passes through the region. The US also conducts operations around the sea to oversee the "freedom of navigation" in the region.