BANGUI, Central African Republic — Thousands of Muslims who tried to flee the violence in Central African Republic’s capital were turned back by peacekeepers Friday, as crowds of angry Christians shouted “we’re going to kill you all.”

The convoy was turned back as France announced it would send 400 more soldiers to its former colony mired in unprecedented sectarian fighting.

The U.N. chief, meanwhile, warned Friday that in Central African Republic “the very fabric of society, woven over generations, is being ripped apart.”

“We must live up to the promises made around this table to act swiftly and robustly in the face of such bloodshed,” U.N. Secretary-General Ban Ki-moon told the Security Council. “We cannot claim to care about mass atrocity crimes and then shrink from what it means to actually prevent them.”

In Bangui, some cars carried as many as 10 people as the convoy made its way through the capital, the second such mass exodus in a week. Christians gathered alongside the road to taunt the Muslims, many of whom have been targeted by murderous mobs in recent weeks.

But the convoy was turned back because peacekeepers feared it would be attacked when going through some volatile parts of Bangui.

The procession of vehicles was halted in the Miskine neighborhood, where one vehicle tumbled into a ditch on the side of the road. On the orders of a Burundian captain, African peacekeepers went vehicle-to-vehicle instructing everyone to return to a local mosque.

Peacekeepers stopped the group before it passed through neighborhoods where fresh fighting had erupted Friday. At least one person was killed in a grenade attack by Christian militiamen, according to witnesses at a nearby mosque.

French peacekeepers had to evacuate two other severely wounded people from an angry crowd that set tires on fire and was shouting anti-Muslim and anti-French slogans.

Tens of thousands of Muslims have fled for their lives as Christian militiamen and crowds of angry civilians have stepped up their attacks in recent weeks. Muslims have been killed by mobs almost every day and their bodies have been mutilated and dragged through the streets.