During the attack, which occurred on Thursday, gang members used automatic weapons to shoot at the town's inhabitants. At least seventy people were killed, including around ten women and three infants, according to the human rights organization OHCHR.
"We are appalled by Thursday's gang attacks in the town of Pont-Sondé", says Thameen Al-Kheetan, spokesperson for OHCHR, in a statement.
In addition, 16 people were seriously injured, while dozens of houses and cars were set on fire.
"It is now crucial that the authorities conduct a swift and thorough investigation of the attack, hold those responsible accountable, and ensure redress for the victims", says Thameen Al-Kheetan.
Last week, OHCHR released a report showing that more than 3,600 people have been killed in gang violence in Haiti this year.
Haiti, one of the world's poorest countries, has been plunged into chaos and anarchy since criminal gangs took over the capital Port-au-Prince. As a result, security and the healthcare system in the country have largely collapsed.
During the first half of the year, violence forced around 600,000 people to flee, according to OHCHR.