"The Americans are undermining us now. They are manipulating ... the peso weakened," Xinhua news agency quoted Duterte as saying in a speech at the Philippine marine headquarters in Taguig.
The Philippine peso hit a seven-year low on Monday, closing at 48.25 to a dollar, the weakest since the close of 48.335 on September 15, 2009.
Duterte told the marine troops that "the Americans are bullying the Philippines," adding that the US has disrespected the Philippines.
The Philippines is a treaty ally of the US, with Manila depending too much on the US for military and other assistance.
However, Duterte said the US "cannot understand a friend".
"Instead of helping us, they will attack you," he said.
If the US will continue putting pressure and manipulating the Philippines, Duterte warned, "I will have new alliances of commerce and trade."
He begged for the understanding of the marine troops. "This Republic will rise. This Republic of the Philippines will continue to be great," he said.
"Time will come that we don't need them anymore. We will survive on our own. We fight our wars on our own and we will win as a country," Duterte said.
Some sectors blamed the depreciation of the peso on Duterte's acerbic statements against US President Barack Obama and the United Nations.
However, Budget Secretary Benjamin Diokno told a news briefing at the Malacnang presidential palace that Duterte's statement has nothing to do with the peso depreciation, saying the weakening of the peso is "a result of the strengthening of the dollar, more than weakening of the peso".
"And why is the dollar strengthening? Because of the impending increase in the interest rate by the Fed. This has been ongoing for several quarters already," Diokno said.
