Moroccans take part in a protest condemning a crackdown on Rohingya Muslims in Myanmar.
The ceasefire would begin on Sunday until October 9, the statement said late Saturday night.
ARSA's statement urged humanitarian aid to all victims of the crisis "irrespective of their ethnic of religious background".
It also called on the Myanmar government to cease all military offensive operations and participate in assisting the victims.
At least 290,000 ethnic Rohingyas have fled to neighbouring Bangladesh since August 25 after escaping violence in Rakhine, according to the latest UN figures.
Yanghee Lee, the UN Special Rapporteur on Human Rights for Myanmar, on Friday said that at least 1,000 people were killed in the violence over the past two weeks, though she said that figure is "very likely an underestimate", CNN reported.
However, the Myanmar government said that only 421 people have died.
The Rohingyas are considered to be among the world's most persecuted people. The predominantly Buddhist Myanmar considers them Bangladeshi but Bangladesh says they are from Myanmar, CNN reported.
Rohingya militants killed 12 security officers in border post attacks, according to state media.
In response, the military intensified "clearance operations", driving thousands of people from their homes.
Satellite photos released by Human Rights Watch show entire villages torched to the ground in clashes between Myanmar's armed forces and local militants.
In northern Rakhine state there are reports of at least another 30,000 Rohingyas trapped in hilly terrain without basic supplies of food, water or medicine, according to activists.