In a statement released by spokesperson, The UN chief reiterated that attacks against UN peacekeepers could amount to a war crime.
He called on the government of CAR to investigate the incident and swiftly bring those responsible to justice.
Mr. Guterres also expressed his condolences to the family of the bereaved, as well as to the Government of Mauritania, where the deceased and wounded peacekeepers hail from.
The attack, targeting a convoy escorted by troops from the UN peacekeeping mission in the country (MINUSCA), took place on Thursday morning near the town of Alindao, which is located along the restive Bambari-Bangassou road corridor.
The attack is believed to have been carried out by so-called anti-Balaka elements, who are operating in the area.
Fighting between the mostly Christian anti-Balaka militia and the mainly Muslim Séléka rebel coalition has plunged the CAR into civil conflict since 2012.
A peace agreement was reached in January 2013, but rebels seized the capital, Bangui, in March of that year, forcing President François Bozizé to flee.
Concerned with the security, humanitarian, human rights and political crisis in the CAR and its regional implications, the Security Council authorized the deployment of MINUSCA in 2014 with the protection of civilians as its utmost priority.