WASHINGTON (AFP) - The Pentagon said on Friday that American forces will continue normal operations despite China scrambling fighter jets to monitor US and Japanese aircraft in Beijing's newly declared air defence zone.

China's announcement last weekend it was extending an air defence identification zone over islands disputed by China and Japan was disregarded by several nations, and US B-52 bombers entered the area.

The United States, South Korea, Japan and other countries have accused Beijing of increasing regional tensions with the air defence zone.

But the scrambling of "several combat aircraft" by China, including at least two fighter jets, according to the state news agency Xinhua, threatens to escalate the situation.

"We'll continue to partner with our allies in the region and operate as normal," Lieutenant-Colonel Erik Brine, a Pentagon spokesman, said on Friday, without elaborating.