Philippine President Rodrigo Duterte lashed out anew at the United States on Tuesday and said it could forget a bilateral defense deal if he stayed in power long enough, in the latest jarring statement from Manila about the future of the alliance.

The fresh broadside from Duterte came as he was about to board a plane for an official visit to fellow U.S. ally Japan, a big investor in the Philippines that is becoming nervous about its apparent pivot towards rival power China. The volatile, crime-busting Duterte had on the eve of the visit softened his remarks last week about a "separation" from Washington, telling Japanese media he wasn't planning to change alliances and was only seeking to build trade and commerce with China.

But he pulled no punches on Tuesday when he said he hated having foreign troops in the Philippines and told the United States not to treat his country "like a dog with a leash". Commenting on a visit to Manila on Monday by Daniel Russel, an assistant secretary of state, Duterte said Washington should forget about an Enhanced Defense Cooperation Agreement (EDCA) with the Philippines if he were to stay in charge longer.

He did not elaborate on what staying longer meant. In the Philippines, a president is allowed only one six-year term in office. The remarks were another perplexing swing from Duterte, who last week announced in China his "separation" from the United States, before assuring that ties were not being severed and he was merely pursuing an independent foreign policy.

His latest swipe at Washington could rattle Japanese Prime Minister Shinzo Abe, who wants to keep ties with the Philippines tight. In a composed reading of a statement prior to departure for Tokyo, Duterte described Japan as a true friend that had played a "preeminent and peerless role" as a big investor and Philippine development partner.