LOS ANGELES, CA (Catholic Online) - Fleeing to the border - or nearby Syrian towns and villages, Aleppo refugees have bivouacked in schools and other public buildings. Mattresses, hygiene items, food and drinking water remaining short supply.   

The U.N.'s Under-Secretary-General for Humanitarian Affairs Valerie Amos says that exact numbers of the ongoing crisis are hard to come by. "It is not known how many people remain trapped in places where fighting continues today," Amos said.

The northern city of Aleppo was at onetime Syria's commercial and cultural hub. The city has since been wracked by bloodshed and fighting, after popular anti-government protests spurred a bloody crackdown by President Bashar al-Assad's forces.

Aleppo has become a major focal point in the war over the past few days. After taking over surrounding towns and villages, rebel fighters have pushed to try to control the city itself, managing to secure locations and even set up checkpoints.

Parts of Aleppo now appear largely devoid of civilians. Rockets and mortar shells had fallen and continued to fall in many residential areas, while Syrian troops defending a military base located just north of the city fired into neighborhoods.

Activist Abo Hamdi says that government forces, tanks and heavy machinery have tried to overrun the neighborhood of Salahuddin, saying that opposition Free Syrian Army fighters have brought in ammunition and taken positions around the neighborhood.

"The situation in the city of Aleppo is very critical and quite serious," he said. "We are trapped in this neighborhood, but the ... Free Syrian Army is preparing for fierce battle."

The Syrian army has recently claimed to have overrun part of the city's rebel-held Salaheddin district. The claim was denied by a Free Syrian Army commander.

"The Syrian army took control of part of Salaheddin district and continues its offensive," a security source in Damascus said.

Activists on the ground reported that a string of rebel-held districts in Aleppo were shelled or hit by small-arms fire during the night.

Outside of the city, rebels seized a strategic checkpoint after a 10-hour battle, securing them free movement between the northern city and Turkey, a FSA commander said.

By securing the checkpoint, the rebels now control a direct route between the Turkish border and the commercial capital.

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