Both sides have clashed sporadically since Renamo challenged the results of the southern African nation's 2014 elections.

Analysts say competition over natural resources could also be exacerbating unrest - Mozambique is on the verge of developing huge offshore gas reserves which could transform one of the world's poorest countries into a middle-income state.

Renamo leader Afonso Dhlakama announced a seven-day truce a week ago after what he described as a long and constructive telephone conversation with Nyusi. The ceasefire extension followed another call between the two rivals.

"It is reassuring that both sides (agreed to ceasefire) so things can go well and provide peace for Mozambicans," Dhlakama, who is in hiding, told reporters in a teleconference.

"I am the head of the family. I am Mozambican and we are really doing this to reduce the deaths in Mozambique."

Members of the current government and Renamo fought on opposing sides in a civil war from 1976 to 1992 that killed an estimated 1 million people.

Dhlakama and Nyusi have not met face-to-face since February 2015 and distrust between the two has led to several ceasefires collapsing since Nyusi won the disputed 2014 vote.

Since the poll, Renamo has demanded it rule in the six provinces where it won the most votes, while the government has called for the opposition to disarm before opening discussions.

Fighting between the two sides usually takes place in the remote interior, making it difficult to assess the extent of the conflict.

Early last year, tens of thousands of Mozambicans fled across the border into Malawi to escape violence and alleged human rights abuses.

(Writing by Joe Brock; Editing by Andrew Heavens)