(CNN) -- The United Nations predicted a jump in the number of Syrian refugees and appealed for nearly half a billion dollars to help meet their needs as a major rebel offensive in the country's largest city, Aleppo, got under way Thursday.
Here are the latest developments in the Syrian civil war.
Refugee numbers could skyrocket as displaced live in squalor
The number of Syrian refugees in neighboring countries could reach 700,000 by the end of the year, the U.N. refugee agency said Thursday. That figure would represent about 3% of the country's population.
The agency gave the number in an announcement seeking $487.9 million to support Syrian refugees. The United Nations is leading 52 humanitarian organizations in the effort.
The funds would go toward the soaring number of refugees flocking to Jordan, Lebanon, Iraq and Turkey.
In March, the United Nations predicted that as many as 100,000 Syrians could become refugees by the end of the year, but that figure was surpassed in July. The new projection indicates the worsening situation on the ground.
There are 294,000 Syrian refugees registered or awaiting registration in neighboring countries, the agency said.
In northern Syria, people fleeing the war endure filthy conditions at an impromptu encampment. Thousands of Syrians were being turned back at the border with Turkey, which said its facilities were overfilled.
Children were scavenging in surrounding fields for twigs to use for cooking fires as women line up next to a water tank that was pumping milky-looking water.
Many of the residents told stories of having fled towns that were pummeled by rockets and airstrikes.
Jihadists claim responsibility for bombing
A jihadi paramilitary group formed during the Syrian uprising claimed responsibility for an attack Wednesday on the Syrian army headquarters in Damascus.
In a statement posted on jihadi Web forums, the Al Nusra Front vowed to launch more attacks to "liberate the people of Syria from the tyrant," a reference to President Bashar al-Assad.
It said its fighters started the attack by detonating a suicide car bomb outside the building, and then had four attackers posing as security guards infiltrate the compound.
The state-run Syrian Arab News Agency said four Syrian guards were "martyred" and 14 other people, including civilians and members of the military, were wounded in two "terrorist bombings" Wednesday targeting the General Staff building in Damascus.
"Decisive battle for Aleppo"
In a telephone interview, Free Syrian Army Col. Abdu Jabar Agadi said rebel troops had launched an offensive he called, "The Decisive Battle for Aleppo."
"I cannot provide any more details of the battle out of tactical concern for troops but, God willing, we will be victorious soon," he said.
Abdulla Yasin, a spokesman for FSA Aleppo, said thousands of FSA fighters were involved in the offensive.
"The FSA will push forward across multiple fronts to make major gains in Aleppo," he said. "This battle will never ever end until we have victory in Aleppo."
He said government forces appear to be "at a weak point and stretched thin."
The government-run SANA news agency said "terrorists" had fired on citizens protesting against terrorist groups in Aleppo.
"A unit of the armed forces targeted a gathering for terrorists in al-Bazeh Square in the old city of Aleppo killing a number of them," it said. "Army forces also, targeted two terrorist dens in al-kallasa and killed them all."
At least 115 people died in attacks nationwide Thursday, the LCC said.
On Wednesday, the single-day death toll hit 343, the highest since the unrest started last year, an opposition group said.
"The regime is escalating the violence at every possible opportunity, and it is proof that it is determined to crush the revolution by any means necessary," said Rafif Jouejati, an LCC spokeswoman.
The second-deadliest day was August 25, when 330 people were killed, according to the opposition group.
Syria said authorities "stormed a terrorists' hideout" in Hama and seized weapons, including Russian rifles.
"On Wednesday evening, authorities destroyed a number of cars for the terrorists which were loaded with weapons and ammunition near al-Zohouri Mosque in al-Qseir city in Homs province," SANA reported.
A pipeline carrying crude oil exploded before dawn Thursday, creating a large fire, and unknown men kidnapped the station's manager, the opposition Syrian Observatory for Human Rights said.
SANA said that "an armed terrorist group on Wednesday evening detonated a crude oil transfer pipeline" and that another such group had "kidnapped engineer Ayman Shaqqouf, director of Tal al-Baiyda oil station."
The Syrian crisis broke out in March 2011 after unarmed protesters, inspired by the success of popular uprisings in Egypt and Tunisia, took to the streets demanding political reform and an end to four decades of rule by the Assad family.
The movement devolved into an armed conflict after a brutal and continuing crackdown by regime forces.
Since the unrest began, more than 30,000 people have been killed, the opposition Syrian Observatory for Human Rights said.
CNN's Hamdi Alkhshali and Ivan Watson contributed to this report.