At least 23 passengers were killed and 16 wounded after gunmen opened fire on a local bus in northern Honduras.
The bus was carrying mostly women and children
The shooting happened in the city of Chamelecon, 200km (125 miles) north of the capital, Tegucigalpa.
The bus - carrying mainly women and children - was driving through a busy neighbourhood when it was surrounded by and sprayed with automatic gunfire.
President Ricardo Maduro called it a "barbaric and cowardly act" and said a hunt was on to find the killers.
Reports say that at least four of the dead are children.
Deputy Commissioner Wilmer Torres said the bus was forced to the side of the road by cars that pulled up at its front and back.
The attackers got out of the cars and sprayed the bus with bullets at 1940 local time (0140 GMT).
Mr Torres said 16 passengers died on board the bus and a further seven died after being taken to hospital in nearby San Pedro Sula city.
Local hospitals were on alert as the wounded were brought in.
The attackers left behind a note saying they represented a revolutionary group opposed to the reintroduction of the death penalty in Honduras.
They also challenged a number of leading politicians who have come out strongly against organised crime.
Mr Torres said a member of one of Honduras' powerful criminal gangs, the Mara Salvatrucha, had been arrested in connection with the attack.
President Maduro offered his sympathy to the families in a television and radio broadcast, and said he would be visiting them personally.
"What happened tonight is a barbaric and cowardly act," he said.
He said the attack was not a threat against him or his ministers, but "an attack against all Hondurans."
He said the police and military had joined forces to find the attackers, and a reward of $50,000 (£26,000) for information leading to their capture was being offered.
"I'm asking the country to have confidence in their government," he said.