Two journalists and a police officer died and at least seven others were wounded in the shooting before the reopening of a hospital wing in Port-au-Prince.
The United States is rushing support to Haiti’s depleted police force, which is awaiting international help as it tries to restore order and quell violence.
With violence overrunning his country, Prime Minister Ariel Henry said he would step down once a transitional council was established. But it was unclear when that would happen.
As gangs have united in concerted attacks against the state, the prime minister is stranded in Puerto Rico, and food, water, fuel and medical care are in short supply.
Martine Moïse, the widow of President Jovenel Moïse, was charged by a Haitian judge with conspiring in his assassination. She was seriously injured in the attack.
A Haitian prosecutor has issued a criminal complaint naming several people as potential conspirators in the assassination of President Jovenel Moïse, including his wife.