The peacekeeping mission said it "strongly condemns the use of unidentified device explosives by armed groups in the Central African Republic."
The UN mission said the two seriously hurt were helicoptered to the town of Bouar for treatment at a MINUSCA-run hospital. On Thursday, three Tanzanian peacekeepers were wounded in a mine explosion in the west.
Mines have killed eight people, including two women and a five-year-old child, in the restive northwest since August, according to MINUSCA.
The country of five million, one of the world's poorest and ranked the second least-developed, has long been plagued by mostly sectarian unrest, which has displaced hundreds of thousands and spawned a major humanitarian crisis.
In recent months, the long-running conflict between rebels and government forces has switched gears, with armed groups driven out of the main cities increasingly resorting to guerrilla tactics, including laying mines.
After several years of a simmering continuation of the civil war that erupted in 2013, recent months have seen a spike in violence.
President Faustin-Archange Touadera declared a unilateral ceasefire in October and his government claims to have recaptured 90 percent of the nation's territory.
But widespread insecurity, and a swelling food crisis, persists, especially in the northwest.