The trouble continues to escalate in Chad where small arms fire and artillery shelling are driving people in the countryside, many of them making their way to nearby Cameroon:

Shelling and small arms fire erupted here in this capital on Monday, the third day of fighting between government troops and rebel forces, as thousands of residents fled the city in fear, the United Nations said.

The Security Council demanded an immediate end to the violence, urging nations in the region on Monday to help thwart the rebels’ “attempt to seize power by force.”

The fighting has raised the specter of deeper chaos in one the most war-scarred and fragile regions of the world. United Nations officials are particularly worried that the instability in Ndjamena could threaten major relief efforts elsewhere in the country.

Chad has become a temporary home to nearly a quarter of a million refugees from the conflict in the Sudanese region of Darfur, and tens of thousands more refugees from the Central African Republic, according to the United Nations. Beyond that, almost 200,000 Chadians have been displaced by fighting, much of which has spilled into the country from Darfur, making for a vast pool of desperate people who depend heavily on international aid.