Washington rejects Beijing's territorial claims to much of the region, including the Paracel Islands - which are often a source of tension - where China is carrying out five days of exercises until July 5.
Wikoff was echoed by US Seventh Fleet spokesman Joe Jeiley, who said that "operating two carrier strike groups in the South China Sea provides advanced training opportunities for our forces" and gives "combatant commanders significant operational flexibility should those forces be called upon in response to regional situations".
"Should the exercises spill over to Philippine territory then China is forewarned that it will be met with the severest response, diplomatic and whatever else is appropriate", Locsin added.
China's expanding military presence in the contested waters has anxious several of its neighbors, and Washington rejects Beijing's territorial claims to much of the region, including the Paracel Islands.
The US Navy conducted massive drills in the South China Sea on Saturday, with two aircraft carriers involved in the exercises. He said the actions of the ruling Chinese Communist Party meant there were "threats to India, threats to Vietnam, threats to Malaysia, Indonesia and the South China Sea challenge".
The Pentagon and other nations have been critical of military drills carried out by China recently.
China claims almost all of the 3.5-million-square-kilometer of the South China Sea, roughly 90%, and accuses USA and other regional actors of violating its territorial integrity.
US Secretary of State Mike Pompeo, for his part, described the Chinese drills as "highly provocative", tweeting that the US "opposes Beijing's unlawful claims [to the South China Sea]".
The Pentagon urged "all parties to exercise restraint and not undertake military activities that might aggravate disputes" in the region, and said it will continue to monitor Chinese military activity. The country has been ramping up its aggressive behavior in the waters since the start of this year as other countries focus on combating the Covid-19 pandemic.
According to the Navy, the last time two carriers were in the South China Sea together was September 2014, when the USS George Washington and USS Carl Vinson Carrier Strike Groups operated there and in the East China Sea. The waters are a major shipping route for global commerce and are rich in fish and possible oil and gas reserves. 31 In April, China created new administrative units for the Paracel and Spratly islands, which are now governed by Sansha city, which China created on nearby Woody Island in 2012.