Duterte said in speeches in Manila on Tuesday that the United States did not want to sell missiles and other weapons to the Philippines.
Duterte said in speeches in Manila on Tuesday that the United States did not want to sell missiles and other weapons to the Philippines, but that Russia and China had told him they could provide them easily.
His comments were the latest in a near-daily barrage of hostility toward the United States that has raised questions about the long-standing alliance that is important to the U.S. strategy of rebalancing its forces toward Asia and countering an assertive China.
Angered by U.S. expressions of concern over his war on drugs, Duterte has called President Barack Obama a "son of a bitch," threatened to call off joint military exercises with Washington and started to contrast the former colonial power with its geopolitical rivals Russia and China.
U.S. officials have downplayed Duterte's remarks, focusing instead on the decades-long alliance which they have sought to bolster in recent years in response to China's moves to enforce its claims over the South China Sea.
The White House said on Tuesday the United States had not received any formal communications from Duterte's government about changing the relationship.
The United States is the single largest provider of arms to the Philippines, according to figures maintained by the Stockholm International Peace Research Institute (SIPRI), which tracks military expenditures globally.
The two countries have become more intertwined militarily in the last two years, holding more exercises and training, and making more U.S. ship and aircraft visits under President Barack Obama's shift of U.S. military forces and diplomatic efforts toward Asia in the face of China's rise.
The Philippines is the largest recipient of U.S. funds in the Asia-Pacific region under the Foreign Military Financing program, which is provided by the United States to help countries purchase American-made weapons and equipment.
It received $50 million under FMF in the 2015 fiscal year.
That dependence on U.S. weapons and systems means the Philippine military would have to re-tool its command-and-control structure if it wanted to switch to Chinese or Russian systems, said Richard Javad Heydarian, a professor at De La Salle University in Manila and a former advisor to the Philippines House of Representatives.
"There will be some problems with configuration," Heydarian said. "It takes years for the Philippines' army to re-orient itself with new technology."
The Philippines spent $3.9 billion on its military in 2015, according to SIPRI data. That spending has risen nearly every year since 2010, when it stood at $2.4 billion, the data show.