Full coverage: The South China Sea Issue

MANILA, Sept. 26 (Xinhua) -- Philippine President Rodrigo Duterte said on Monday that he would open up all avenues of trade and commerce for China and Russia, adding that he is about to "cross the Rubicon between me and the United States."

Duterte said he would open up the airline industry, telecommunications, shipping and even lease land to China and Russia for 60 years renewable for another 60 years.

"I am about to cross the Rubicon with the U.S. It is a point of no return," he said in a speech during an oath-taking event at the Malacanang presidential palace.

The idiom to "cross the Rubicon," means to pass a point of no return, and refers to Julius Caesar's army's crossing the Rubicon River in northern Italy in 49 BC, which was considered an act of insurrection and treason.