Two Cambodian toddlers died when a rocket-propelled grenade believed buried since the country's civil war blew up near their homes, an official said Sunday.

The explosion happened on Saturday in a remote village in northwestern Siem Reap province that was once a battle site for Cambodian government soldiers and Khmer Rouge fighters in the 1980s and 1990s.

The children who died were cousins — a boy and a girl who were both two years old. 

"According to an investigation report, the two toddlers were playing on the ground, digging the soil and may have hit (the grenade) with an object that caused the explosion," Heng Ratana, director general of the government's Cambodian Mine Action Centre (CMAC), told AFP.

He said one child was killed instantly while another died in hospital.

"The war has completely ended and there has been peace for more than 25 years, but the blood of Cambodian people continues to flow because of landmines and the remnants of war," Heng Ratana added.

The accident comes after Cambodia was forced to partially suspend demining operations for several weeks when Washington suddenly halted funding following President Donald Trump's order to freeze foreign aid for 90 days.

But on Friday, Cambodian officials said deminers were to resume clearing unexploded munitions, after the United States granted a waiver to keep funding the work in the country.

The Southeast Asian nation remains littered with discarded ammunition and arms from decades of war starting in the 1960s.

After more than 30 years of civil war ended in 1998, Cambodia was left as one of the most heavily mined countries in the world.

Deaths from mines and unexploded ordnance are still common, with around 20,000 fatalities since 1979, and twice that number wounded.

Last month, two Cambodian deminers were killed while trying to remove a decades-old anti-tank mine from a rice field and a villager died in a landmine blast on his farm.

More than 1,600 square kilometers (620 square miles) of contaminated land still needs to be cleared which leaves approximately a million Cambodians affected by war remnants.

Cambodia had aimed to be mine-free by 2025, but the government pushed the deadline back by five years because of funding challenges and new landmine fields found along the Thai border.