On Sunday, President Jovenel Moïse visited the coastal city of Port-de-Paix, just 11 miles (18 kilometers) from the quake's epicenter.
Images of damaged homes and partially destroyed buildings were circulating on social media, but AFP was not immediately able to confirm their authenticity.
The U.S. Geological Survey said the epicenter of the aftershock was located 9.8 miles (15.8 kilometers) north-northwest of Port-de-Paix, the city hard hit by Saturday's quake.
"Some casualties are possible and the impact should be relatively localized". He reported seeing damage to other buildings as well.
This is a developing story. It was 7.3 miles (11.7 kilometers) below the surface.
Sister Maryse Alsaint walks alongside a school damaged by a magnitude 5.9 quake the night before in Gros Morne, Haiti, today.
Putin calls Sergey Skripal a ‘scumbag’ and a ‘traitor to his homeland’
Russian President Vladimir Putin attends a meeting at the Novo-Ogaryovo residence outside Moscow , Russia , Monday, Oct. 1, 2018. It is to be said that the S-400 missile system is one of the most advanced warfare technology in the world today.
Damage was also reported at the Saint-Michel church in Plaisance and the police station in Port-de-Paix. "I call on the population to be cautious and calm", he said in a statement posted to Twitter.
Haiti's Nord-Ouest department is the poorest part of the impoverished country, with many isolated areas due to the dire state of the roads.
President Jovenel Moise asked worldwide aid agencies to coordinate with local agencies for better relief operations and urged people to donate blood. Residents using saws or their bare hands scrambled to recover metal support rods from the debris for resale, before being chased away by authorities.
A woman watching the disaster unfold, 49-year-old Rosette Jerome, said no one in her neighborhood had been killed but added that a child was seriously injured by a piece of falling masonry.
The agency said damage and injuries were mostly concentrated in the northwest region of the island, where two minor aftershocks were also felt, the agency said.
Thousands of people along Haiti's north coast have dragged mattresses and chairs outside, fearing new aftershocks. A vastly larger magnitude 7.1 quake damaged much of the capital in 2010 and killed an estimated 300,000 people.