"We'll be doing them more and we'll be doing them with greater complexity in the future," Admiral Harry Harris, the commander of the US Pacific Command, told American lawmakers on the growing friction in the South China Sea.
"We'll fly, sail and operate wherever international law allows," Harris, who is set to visit India next week, said. He said China was building military capabilities in the South China Sea leading to escalating tension in the region.
"In my opinion China is clearly militarising the South China Sea," Harris, in a hearing on Tuesday before the Senate Armed Services Committee. "You'd have to believe in a flat earth to believe otherwise," he said.
"China's intent to militarise the South China Sea is as certain as a traffic jam in DC," Harris said in reference to congestion on the streets of Washington.
The harsh assessment from the US military's top commander in the Pacific comes amidst a series of reports of increasing Chinese capabilities on disputed islands in the resource-rich South China Sea.
In Beijing, Chinese Defence Ministry spokesman Colonel Wu Qian said, "I have noted that according to media reports, Adm. Harris made his remarks while seeking additional defense budget funds from Congress."
"We don't interfere in your seeking defense budget funds, but you can't carelessly smear China while asking for more money," Wu said. Last week, satellite images showed China had installed a surface-to-air missile battery on the Paracel Islands near Vietnam. And on Monday, reports surfaced that China is installing a high-tech air search radar that may be capable of detecting US stealth aircraft on one of its man-made islands in the Spratly Islands.
"We must continue to operate in the South China Sea to demonstrate that that water space and the air above it is international," Harris said. Since October, the US Navy has carried out two such freedom of navigation operations in the South China Sea to emphasise saying the missions are an important way of upholding international law.
The Asia Pacific region has witnessed tension after China flexed its military muscle in the South China Sea. The South China Sea is also a major shipping lane. Over half of the world's commercial shipping passes through the area.
China claims almost the whole of the South China Sea, resulting in overlapping claims with several other Asian nations like Vietnam and the Philippines, Malaysia and Brunei.
They accuse China of illegally reclaiming land in contested areas to create artificial islands with facilities that could potentially be for military use.