Many humanitarian workers said they had been prevented from carrying out their work, especially after France's withdrawal of troops - part of the Sangaris military mission in the CAR - last year had led to fears that violence would erupt.
This was the third attack on Red Cross workers this year, but it is hard to say whether they were specifically targeted.
These are not the group's first casualties in the CAR.
"In principle, we shouldn't be targets," Antoine Mbao-Bogo, the president of the Central African Red Cross, told RFI. "I'm actually in tears right now, and the entire Red Cross is appalled and worried."
He said that even though Red Cross workers have died in the past, it has never been this many, during the same attack.
"We don't have guns, or any kinds of weapon.. we're just trying to do our job, which is to help people. Among those killed last week, there were pregnant women killed. They'd come to the health centre to give birth. And they had their throats cut. This is something that goes beyond my understanding."
There are several factors that have caused this resurgence of violence in the CAR.
First, militia violence has intensified in the country, including attacks on UN soldiers and aid workers. And people are worried that the violence could become as widespread as during the chaos in 2013.
"It was clear to me that the growth of intercommunal violence, this pretense, perhaps it's sincere, I don't know, of using ethnic and confessional identity as a cause for killing, brutality, torture, threatening behaviour, that these were the early signs, the early warning signs, of what could rapidly turn into a genocide," said the UN's Under-Secretary-General for Humanitarian Affairs, Stephen O'Brien.
That is why he made his warning. He said he had also consulted very intensively with his fellow UN colleagues in the Human Rights commission, the High Commisionner of Human Rights, and also with the director who has a view to prevent and to warn on genocide.
"And we're all now coming together to do what we can to urge greater presence of the UN for the protection of civilians in what is becoming a very rapid, flare-up in various parts of the southeast, centrel southeast, the east as well as the northwest of the Central African Republic."
Violence has escalated since the withdrawal of French troops from the CAR's Sangaris mission.
Their withdrawal has affected the situation because the Sangaris mission was the only force which had air support and armoured vehicles that it could use quickly and effectively.
"The problem is that the UN troops alone are not mobile enough, meaning that when you've got an incident somewhere, they've got to intervene, but they usually are too late, after the killing of people there has happened. But Sangaris was ready to intervene with helicopters, very quickly and so it was a sort of a safeguard for the UN forces inside the country," French general Dominique Trinquand, the former chief of the military mission to the United Nations, told RFI.
"The other important point is that a UN force is fine, but when you have soldiers who are not able to interact with the population then you've got a problem. A lot of the soldiers inside the UN force are not French speakers, and so they're not able to discuss with the people and to have the right information in order to react very quickly."
French troops have been recalled back to France, for Operation Sentinelle, after France was hit by a string of attacks.
Trinquand says there is a need to re-evaluate where French soldiers should be sent. Their number here in France should at least be reduced, he says.
"10 000 troops, it's a huge number. And Operation Sentinelle has been deployed for more than two years. And that was not the plan initially," Trinquand said.
The French President, Emmanuel Macron, asked the Chief of Defense staff to present a plan to reduce the force and to reorganise Sentinelle.
"My opinion is that you need more police officers, more gendarmes (paramilitary police officers) in France and a military capacity to react, but you don't need to have these many troops on patrol in France. And then these troops could be used in operations outside France, where they are really needed."
Trinquand said that though, of course, France needed some kind of protection, French troops could be a game-changer in countries like the CAR today.