Duterte said Russia would provide about 5,000 assault rifles in a deal to be signed this month, and the Philippine military would no longer have to use second-hand arms.
"We will have the Kalashnikov," he said in a speech to troops, adding that Russia wanted to keep the donation secret.
Moscow's gift would follow China's donation of more than 6,000 assault rifles and 100 sniper rifles, among the fruits of Duterte's efforts to form partnerships with two arms-producing powers that are rivals to the United States.
The United States has for decades been the Philippines' defence treaty ally and its biggest source or hardware and training, providing about $1 billion in equipment since 2000. Duterte has made no secret of his animosity towards Washington and his disdain for the U.S. military alliance.
A senior defence official told Reuters the Russian weapons would arrive later this month, when Russia's defence minister attends a regional meeting. The rifles would be accompanied by millions of rounds of ammunition and dozens of army trucks.
Five Russian warships were due to visit in Manila to deliver the equipment, the official said. Four have visited the country this year, in two separate visits.
Duterte said the military needed to be properly equipped to handle Islamic State loyalists who had established a dangerous foothold in Mindanao in the south.
"They will not disappear, they will regroup anywhere and everywhere," Duterte said.
International / ASEAN/Philippines
Russia to donate Kalashnikovs, trucks and munitions to Philippines
Duterte said Russia would provide about 5,000 assault rifles in a deal to be signed this month
Philippine President Rodrigo Duterte on Wednesday announced that Russia would donate defence hardware to support the military's fight against pro-Islamic State militants, who he said could regroup and attack "anywhere and everywhere".
