A new, more powerful explosion in the afternoon prompted an evacuation order, but deadly and fast-moving flows of superheated material and debris washed over villages before many people had time to flee.
Disaster agency spokesman David de Leon says officials are analyzing the terrain to make a decision.
The National Forensic Sciences Agency said in a report Wednesday that morgues had received the remains of 99 people killed as a result of the eruption. Their chances of having survived in the superheated pyroclastic ash storm are slim to none.
Fuego volcano exploded around noon on Sunday, affecting more than 1.7 million people.
An American military plane has already transported some burn victims to the US for specialised treatment, the US Air Force said.
Rocca noted that ash had fallen across more than half of Guatemala, covering areas where agriculture is crucial.
The IFRC has pledged more than 250,000 Swiss francs ($253,000) to support rescue efforts and said those worst hit would need at least a year to recover.More news: Trump throws G-7 into disarray with tweets after he leaves
It said it made a decision to suspend the search now that 72 hours have passed.
The active volcano is located about 25 miles (40 km) southwest of the capital, Guatemala City.
Hospital officials began working with Guatemalan and US officials to mobilize this effort within 24 hours of the disaster, so the victims would be able to get immediate treatment and care.
It sent huge clouds of ash barreling over the surrounding area, blanketing roads, cars and people in thick gray dust as a river of molten mud carved a path down the mountain, sweeping away entire villages.
"At the request of the Government of Guatemala, we are sending emergency aid, including financial resources to help meet food, water, and sanitation needs for the affected population", the release said.
The children were among the victims of Sunday's eruption of the Volcano of Fire, which buried almost villages in superheated ash and debris.
The most recent official death count of 75 was reported by Guatemala's disaster agency Tuesday night.