Since 2020, different armed groups have carried out attacks and ambushes targeting guards in the park, Africa's largest nature reserve.
In a statement, the park said the attackers were members of the "Mai Mai Kabido," an armed group.
The two guards "were shot and succumbed to their injuries" in Nyamusengera, a section of the park near Lake Edward, which marks the frontier with Uganda.
"This morning we heard the 'crackling' of bullets," said Kambale Muhindo, a worker in Vitshumbi, a fishing village 5 kilometres (3 miles) from the scene of the attack. "A group of poachers had just killed a hippopotamus and to protect themselves they ambushed the guards."
Alongside the two deaths, "six guards have been injured and sent to the Vitshumbi Catholic hospital", said Blaise Kalisha, a human rights activist.
On May 18 this year, four park employees, of which three were guards, were killed. The authorities blamed the same armed group.
Founded in 1925, the Virunga national park has been recognised by Unesco as a world heritage site since 1979.
It is known for its fauna and landscapes, but also for serving as a base for a number of armed groups for more than two decades.