The Unity Alliance, which includes several separatist groups, said in a statement the pause starting on Wednesday reflects the "profound spiritual importance" of the visit and is intended to allow civilians, pilgrims and dignitaries to travel safely.
Cameroonian authorities did not immediately respond to the Associated Press' request for comment.
Government spokesman René Sadi last week said "all necessary arrangements have been made" to ensure a successful visit.
Cameroon's western regions have been plagued by fighting since English-speaking separatists launched a rebellion in 2017 with the stated goal of breaking away from the French-speaking majority and establishing an independent state.
The conflict has killed more than 6000 people and displaced about 600,000 others, according to the International Crisis Group.
Pope Leo, who began his four-country Africa visit this week in Algeria, is set to arrive in Cameroon's capital Yaoundé.
He will lead a "peace meeting" on Thursday in the city of Bamenda, the epicentre of the conflict between separatists and government forces.
A spokesman for the Unity Alliance, Lucas Asu, said in the statement the pause in fighting "reflects a deliberate commitment to responsibility, restraint, and respect for human dignity, even in the context of ongoing conflict".
He said the Pope's visit should remain "spiritual" and not be seen as endorsing any political authority.
Although the number of deadly attacks by separatists has decreased in recent years, the conflict shows no sign of resolution.
Peace talks with international mediators have stalled, with both sides accusing each other of acting in bad faith.
The conflict is rooted in Cameroon's colonial history, when the country was divided between France and the United Kingdom after World War I.
English-speaking regions later joined French Cameroon in a 1961 United Nations-backed vote but separatists say they have since been politically and economically marginalised.
The Pope on Tuesday visited the ancient archaeological sites of Annaba in Algeria, where Saint Augustine of Hippo once lived and worked.
The theologian (354-430 AD) is the namesake of the Augustinian order, to which the Pope still belongs today.
Before his election as head of 1.4 billion Catholics, Leo led the order worldwide.
Leo is the first pontiff ever to visit Algeria, where Islam is the state religion.
Of the country's nearly 48 million inhabitants, only about 9000 are Catholic.
On the first day of his visit, Leo also recalled the fate of 19 nuns and priests who were killed in Algeria during the civil war between 1992 and 2002.
He was unable to visit the monastery of Tibhirine, where militants abducted and then murdered seven Trappist monks in 1996.
The monks have since been beatified by the Church.
The Pope is on an 11-day tour through Africa.
Further stops after Cameroon include Angola and Equatorial Guinea.
The start of Leo's trip to Africa was dominated by criticism from US President Donald Trump.
The US-born pontiff, who was elected in May last year, made it clear that he would not be intimidated by the White House.
Popes have visited Africa time and again over the past few decades.
The continent is one of the regions of the world where the Catholic Church is growing.
There are about 290 million Catholics living on the continent - more than in Europe.
Worldwide, about a fifth (20.3 per cent) of all Catholics come from Africa.
with DPA
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